&L

,U5%°1 eKJT

Journal of the

Lepidopterists' Society

Volume 62 Number 4 22 Dec 2008 ISSN 0024-0966

Published quarterly by The Lepidopterists' Society

THE LEPIDOPTERISTS’ SOCIETY

Executivk Council

John H. Acorn, President Lazaro Roque-Ai.belo, Vice President

William E. Conner, Immediate Past President Michael E. Toliver, Secretaiy Jon Pelham, Vice President Keli.v M. Richers, Treasurer

Carmen Pozo, Vice President

Members at lar^e:

Stephanie Shank Michelle DaCosta

Charles Harp John II. Masters

Todd Stout Michael G. Pogue

Editorial Board John \V'. Brown {Chair)

Michael E. Toliver (Member^ at lar^e)

Brian Scholtens ijounial)

L.awrence F. CiAi.L {Memoirs)

Dale Clark {News)

John A. Snyder {Website)

Honorary Life VIembers of the Society Lincoln P. Brower (1990), Frederic:k II. Bindge (1997), Ronald W. Hodges (2004)

Kim Garwood Kenn Kaufman Harry Zirlin

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Journal of The Lepidopterists' Societi/ (ISSN 0024-0966) is published quarterly by The Lepidopterists' Society, % Los Angeles County Museum of Natural Histoiy. 900 Exposition Blvd., Los Angeles, CA 90007-4057. Periodicals postage paid at Los Angeles, CA and at additional mailing offices. POST.MASTEB: Send address changes to The Lepidopterists’ Society, 7o Natural Plistory Museum, 900 Exposition Blvd., Los Angeles, CA 90007-4057.

Cover Illustration: Massive clusters of monarch bntterilies festoon the boughs of a cedar tree {Cu])rcssus hisitanica) located in the Ojo de Agua arroyo that runs dowm the south facing slope of Cerro Pelon, one of the three major oveiw-intering areas in tlie Monarch Butterfly Bios- phere BeseiA'e in the State of Mexico. Photo by L.P. Brower, 13 (annar)- 2006. (See article on page 177).

Volume 62, Number 4

177

"-s-

(

J

HE

OURNAL OF

Lepidopterists

1 2 7'Wq

OCIETY

Volume 62

200S

Number 4

Journal of the Lepidopterists Societif 62(4). 2008,177-188

MONARCH BUTTERFLY CLUSTERS PROVIDE MICROCLIMATIC ADVANTAGES DURING THE

OVERWINTERING SEASON IN MEXICO

Lincoln P. Brower,

Department of Biology, Sweet Briar College, Sweet Briar, \7rginia 24595, U.S.A.; email: hrower@shc.edu

Ernest H. Williams.

Department of Biolog)', Llarnilton College, Clinton, New York 13323, U.S.A.

Linda S. Fink,

Department of Biology, Sweet Briar College, Sweet Briar, \arginia 24595, U.S.A.

Raul R. Zubieta,

Instituto de Geografia, Ciudad Universitaria, Universidad Nacional Autonoma de Mexico. 04510, Covoacan, Mexico D.F., Mexico.

AND

M. Isabel Ramirez

Centro de Investigaciones en Geografia Amhiental, Universidad Nacional Autonoma de Me.xico, Antigua Carretera a Patzcuai'o,

8701, CP 58190, Morelia. Michoacan, Mexico.

ABSTRACT. Monarch buttei'flies form dense clusters in their o\ en\antering colonies in the mountains of central .Mexico, where forest cover provides protection from environmental extremes. We tested the hvpothesis tliat the clustering behavior of the butterflies further moderates the microclimate they experience. We inserted hygrochrons (miniaturized digital hygrothennographs) into clusters for two-day periods during the 2006-07 and 2007-08 winters and compared temperature and relative humidiri' inside and outside the clusters. The inside of the clusters re- mained significantly warmer at night and significantlv cooler during the day, with higher relative humiditv during both day and night. Conse- quently. the butterflies inside the clusters may have gained some protection from freezing, reduced their rate of lipid liuruing, and low'ered their rate of desiccation. Tire differences were small, but these studies w'ere conducteil during calm, moderate conditions, and the effects are likely to be more pronounced under more severe weather, including mid-winter storms and late season ariditv'. The microclimatic advantages of the monarchs’ clustering behavior on fir boughs add to the known repertoire of the butteiifies' overwintering adaptations to the high altitmle envi- ronment that they occupy each year from November through March.

Additional key word.s: aggregation, insulation, clustering behavior, temperature, humiditv.

Aggregation behavior is widespread in the animal kingdom and confers two major adaptive advantages to individuals: protection from predators and fav'orable modification of microclimate. Forming tight groups in many species of vertebrates and invertebrates reduces the probability, through the selfish herd effect, that any one indiUdual will be killed (Hamilton 1971; Gamberale & Tnllberg 1998). This advantage is enhanced when the

individuals are chemically defended (Brower 1984; Bough 1988; Sillen-Tullberg & Leimer 1988). The monarch butterfiy (Danaiis plexippiis L., Lepidoptera, Danainae) is a classical example. The extreme densities of ovenVntering butterflies reduce the likelihood of any indivfidual being attacked, as does their ability to store cardiac glycosides that are emetic to vertebrate pretlators (Brower et al. 1967; Brower 1984; Seiber et

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Journal of the Lepidoptei-usts' Society

al. 1986). These poisons reduce avian predation by reinforcing learned visual aversion of the butterflies' orange, black, and white warning coloration. Though sulistantial predation in the ovenwntering colonies in Mexico occurs by orioles and grosbeaks (Calvert ct al. 1979; Fink & Brower 1981: Brower & Calvert 1985) and by certain species of mice (Brower et al. 1985), the inaiority of birds (Fink ct al. 1983; Brower & Fink 1985) and mice (Glendinning & Brower 1990) are substantially deterred.

Microclimatic effects also inHnence aggregations, with animals often choosing sites w'here conditions are moderated. Nnmerons insects are knowai to respond to small differences in temperature and hnmiditv (Clondsley-Tliompson 1962; Waldbaner 2000); for example, ladybird beetles and weevils aggregate wdiere Immiilitv is higher (Simpson & Welborn 1975), and cutworm moths aggregate in alpine tains (White et al. 1998), where temperatures are less e.xtreme. Also, animals may create moderated conditions within their aggregations. For example, cockroaches and crickets generate higher hnmiditv within their clusters (Dembach & Goehlen 1999; Yoder et al. 2002). Onr study explored possible microclimatic aih antages that

monarch butterflies derive from their clnstering beha\lor.

One of the great biological spectacles on earth is tlie aggregation behavior of monarch butterflies at their ovenvintering sites in the Transverse Neovolcanic Range in central Mexico (Brower 1995). Arriving on at least tw'elve separate mountain massifs (Slayback et al. 2007; Slayback & Brow'er 2007) in early November, the butterflies form extremely dense clusters on the boughs and trunks of coniferous trees in colonies that, by mid- December, range in area from 0,01 to 6.14 hectares (Fig. 1). The large.st combined area of monarch clusters occurred during the 1996-1997 oveiAvintering season (Missile 2004; Slayback et al. 2007), with an estimated combined total of 18 hectares of forest festooned with butterflies. Recent estimates indicate that there are at least 50 million butterflies per hectare (Brower et al. 2004), so that the 1996-1997 aggregations contained about 900 million monarchs.

Even though the ovenvintering area of monarch biitteillies is south of the Tropic of Cancer, the 3000 m pins elevation ol the mountains on which they form their colonies subjects them to freezing temperatures. Their greatest natural mortality occurs liy freezing to

Fig 1. Aerial pliotograpli of the Piedra Ilerrada ovenvintering colony in an oyaniel fir forest in the state of Mexico. In mid to late Dec 2006, this small colony occupied 0.27 ha (Rendon-Salinas et al. 2()07). The butterflies likely av'oid clustering in the tree tops in order to avoid freezing from exposure to the cold night skvv 1.3 Feb 2007.

\'OLUME 62, Number 4

179

Fic:. 2. The density of clustering nionarchs varies according to tlie foliage architecture ol the tree species on whicli they settle. Note the exceedingly dense clusters on the tnaniel fir (left foreground) and the much smaller hall like clusters on the pine (right background). Photo taken in the Ojo tie Agua ravine on Cerro Pelon in the state of Me.xico, 13 F'eh 2004.

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Journal of the Lepidoptekists’ Society

death after northern rain and snowstorm incursions wet them, followed hy plunging temperatures as the weather clears. One such storm in January 1981 was estimated to have killed more than 2.5 million monarchs in a Sierra Chincua colony (Calvert ct al. 1983), and in januaiy 2002 a major wdnter storm killed nearly half a billion monarchs across the ovenvintering region (Brower et al. 2004).

By forming their colonies in dense coniferous forests and by avoiding the tree tops, monarchs derive microclimatic protection from the forest canopy that acts as a blanket and reduces the rate of radiant heat loss to the skw (Calvert & Brower 1981). This blanket effect is tlramatically demonstrated by large differences in bofh nuLximum and minimum daily temperatures inside the forest compared to nearby open areas (Brower & Calvert 1985). A second microclimatic advantage of the forest canopy is that it acts as a partial umbrella and helps to prevent the butterflies from getting wet during wdnter rain and snowstorms (Anderson &: Brower 1996). These authors also discovered that ovenvintering monarchs can withstand freezing at body temperatures dowTi to about -8 C°, but their natural cnoprotection is substantially lost if their bodies become wet. WJien the forest is thinned, holes are punched iu the blanket and umbrella, and both the thermal and sheltering adwmtages are diminished (Calvert ct al. 1983).

Based on obsenmtions of the sites dating back to 1977, the three most utilized tree species are, iu order of importance: the oyamel fir, Abie.s religiosa II. B. K. (Pinaceae), the smooth bark Mexican pine, Pinus pseudostrobus Lindl. (Pinaceae), and the Ale.xican cedar, Cupre.ssus lusitanica Aliller (Cupressaceae) (synonvm of C. lindleyi; GRIN, 2007). The architectures of individual clusters are determined by the growth form of the boughs and needles of the tree species on wJiich the butterflies settle (Figs. 2, 3A-C). Anderson & Brower (1996) found that butterflies inside fir clusters gain an important microclimatic advantage: they did not get as wet as those on the outside (Fig 4). The authors deduced that individuals within the clusters would more likely survive subfreezing temperatures.

This paper presents the results of field experiments begun in 2007 and repeated in 2008 designed to test the hyjDothesis that butteiilies inside the clusters are insulated by those on the outside, with three possible microclimatic advantages. First, during lethal temperature drops, the butterflies inside may remain warmer. Second, during the day when temperatures climb, the inner butterflies may stay cooler, thereby presening their lipid resen^es. Lipids are critical both for winter suiwival (Masters et al. 1988) and for the suniving monarchs’ spring remigration back to the Gulf

Coast (Malcolm et al. 1993). Third, the butterflies on the inside of a cluster may enjoy higher humidity, thus reducing evaporation and desiccation, which intensify as the diY season advxmces and millions of monarchs engage in long to-and-fro flights to drink waiter.

Materials and Methods

Location of the study sites. The colonies studied in both years w^ere located in the Sierra Chincua massif in Michoacan, Mexico. Their coordinates were determined using a Garmin-CS GPS unit and the Angangueo topographic map (INEGl 1999). On 8 January 2007, the position of the colony near its upper boundaiy w^as 100° 17' 58"M7 19° 40' 31"N, at an elevation of 3256 m. This is at the head of the w^estern- most tributan' leading dowm into the Arroyo Hondo. On 5 Februaiy 2008, the colony was located 1.1 km to the east of the 2007 site, slightly east of the eastern-most tributaiy of Arroyo Hondo, at appro.ximately 100° 17' 19"W, 19° 40' 06''N, at an elevation of 3317 m. Both of these areas have hosted ovenvintering colonies in almost exactly the same positions as reported nearly 30 years ago and in numerous ov'envintering seasons since then (Galvert & Brower 1986; Missile 2004).

I lourly temperature and humidity data on the same dates were recorded by an electronic weather station (Weatherllawk, Model 232, Logan, UT) located on the Monarch Butterfly Biosphere Reseiwe (MBBR) Field Sfation ou El Llano las Papas (100° 16' 6.2"W, 19° 39' 41.9"N, elev'ation 3160 m). The field station is on the eastern edge of the Sierra Ghincua in an open llano (field) adjacent to an oyamel fir forest. It is approximately 3.6 km ESE of our 2007 e.xperimental site, and approximately 2.5 km ESE of our 2008 site. The WeatherHawT recorded temperature each hour averaged over the previous hour. All data were dowTiloaded into spreadsheets for analyses. A hygrochron attached to the underside of the weather station provided a direct comparison to the measurements of the other hygrochrons used in the experiment.

Temperature and humidity measurements of the elusters. Eor successive nights in both 2007 and 2008, we measured temperature and relative humidity inside and immediately outside monarch clusters that had assembled on the boughs of oyamel fir trees within the Ghincua colony. The recording devdces (Fig. 5) were iButton Hygrochrons (model DS1923, Dallas Semiconductor Goiporation), which are small electronic disks (1.59 cm by 0.64 cm). The hygrochrons were set to record an instantaneous reading once every twenty minutes.

For 2008, the hygrochrons were evaluated by

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Fig. 3. (a) An early winter cluster ol nionarchs on an oyainel Hr, likely the optimal tree species substrate for the butterflies to hold onto and form e.xtremely dense, bag-like clusters having a large volume to surface area ratio. Photo taken in the Sierra Chincua colony in the state of .Vlichoacan, 9 Dec 2006.

comparing their reading.s uiicler identical conditions. All liygrochrons were placed in the same plastic bag to record temperature and humidity every 20 min during 13 hours of warm, room-temperature conditions (40 records) and 10 hours of cold, refrigerated conditions (30 records). We compared the average of the test reatlings for every pair ol liygrochrons used in an inside- outside comparison across a cluster. When the average reading of one hygrochron under test conditions was less than the other, that difference was added to the measurements from the field of the first hygrochron. We applied adjustments to the field data separately for day measurements (adjustments from the warm readings) and night measurements (adjustments from

Fig. 3. (b) An early winter cluster on a cedar tree, which has flatter ueetlles and is likely a less ojitimal substrate for dense clusters than tlie fir. Photo taken on the Llano de los Ties (iob- ernailores colony, on Cerro l^elon in the state ol Mexico, 1 1 Dec 2006.

the refrigerated readings). These sensors are tidvertised as having an accuracy of +0.5 °C and a resolution ol 0.6% RH. We did not compare their accuracy against known standards, Imt by our measurements, the liygrochrons gave such little variation in their reatlings that, in comparing tfiem, we found the S.D. of tlie differences in temperature of each pair to range (roin only 0.03 to 0.07°C. That meant that each sensor gave highly consistent readings and that, with precision, paired hygroclions could measure differences of less than 0.1°C. Relative Innniditv readings were more variable, with S.D. of all painvise differences ranging from 0.58 to 0.97%.

Inserting the liygrochrons into the clusters.

Four (2007) or tliree (2008) liygrochrons were attaclied with ©Velcro to 89 cm long by 0.95 cm diameter wooden dowels at appro.xiniately 20 cm inten als. The end of a #18 Rvisted nylon Rvine leading off a spool was then attached with duct tape to the top of the hygrochron dowel. To lift the string that was attached to the hygrochron dowel, we used a 3 in e.xtensihle pole to which a second dowel with a bent liook nailed into its end was taped. We raised the pole so that the hygrochron dowel attached to the string hung directly over the cluster center. By gently playing out the string through the hook to avoid disturbing tlie cluster, the dowel was lowered into the cluster center. Once vertically positioned, we carefnllv twisted the pole to release the string from the hook and then secured the string to hold the dowel in place with at least one liygrochron inside and one outside the cluster (Fig. 5).

Experiments. Tlie goal was to compare the temperature and relative hnmidity inside and immediately outside tlie monarch clusters. In 2007,

Fig. 3. (c) A late winter ciu.ster on a pine tree, the least favor- able of the tl iree iiiajoi' coniferous substrate.s for dense clusters. The ball-like pine clusters are smaller than those that lorm on the firs and cedars, thus pnn iding less niicrocliniatic protection. Photo taken in the Ojo de Agua ravine, 9 Mar 2006.

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Journal of the Lepidopterists’ Societa’

Fig. 4. Moiiarchs clustering; on o\ amel fir hranclies wetted hv ail earK' Deceniher stonn. Tlie small siK’erish spots are u'ater drops. Note that the fir houghs prm ide an umbrella effect and that there are few raindrojis on the butterflies. This microcli- matic effect is greater in larger clusters where the butterlfies in- side the cluster ha\ e less or no water on them. Photo taken in the Sierra Cliiucua .Arro\o I londo colon\" in the state of Miclioa- can. 9 Dec 2006.

preliniinan' studies were run on two clusters (Al, A2), while also positioning a single outside hvgrochron on a dead oyainel tree bninch less than 10 m away (A3). The dowels were in place from 1540 on S Jan 2007 to 0940 on 10 Jan 2007. We used hinocnlars to confirm tliat the dowels maintained their positions inside the clusters thronghont the e.xperiment.

We repeated the experiment in Febrnaiv 200S, placing dowels with sensors into six clusters (B1-B6). To obtain repeated ambient measures inside the colony, three control hygrochrons were attached to another dowel (B7) that we hung from an oyamel tree branch on the western edge of the colony at about the same height as the study clusters. Three dowels (B1-B3) were in place from 1700 on 5 Feb to 1530 on 7 Feb, and an additional three dowels (B4-B6) were in place from 1200 on 6 Feb to 1500 on 7 Feb. The data from one cluster (B2) were later deleted from the analysis because butterflies subsecjnently surrounded all the hygrochrons, so there was no inside-ontside comparison. The five other dowels xlelded readings for txvo days (10 day-time comparisons), while tx\'0 dowels

Fig. 5. The e.xperimeutal dowel inserted into experimental cluster 2 on an oyamel fir bough ou 9 |an 2007. Tlie bottom of the dowel with an exposed hvgrochron is evident; the other tliree In-grochrons are inside the cluster. The inset is a closeup of a hvgrochron attached to a dowel with \Tlcro.

recorded tor two nights and the other three for a single night (7 night-time comparisons).

The hygrochrons recorded temperature and relative hnmiditx' eveiy 20 min, but for analysis, we standardized the times for comparison as day, f 2()()-170(), and night, ()(M)()-()8()0. These were the times recorded by the ambient hygrochrons as being the warmest and coolest periods of a 24 hour day and thus the times when insulating of the clusters would be the most important.

We also recorded \\4nd speed in the colony during the 2008 experiment with a Wind Speed Smart Sensor attached to a HOBO Alicro Station (Onset Computer Corp.).This instrument vlelded the average and maximum wind speed during each five-min time block from 1800 on 5 Feb 2008 to 1430 on 7 Feb 2008.

Description of tlie clusters. Qiuilitative obseiwations indicated that there were fewer large clusters during both ovenrintering seasons than has been the case in the past, and they were less dense than in most previous years. Daxtime temperatures were high enough that care was necessaiy not to disturb the butterflies and cause them to "e.xplode" ont of the clusters. Over the course of the 2007 experiment, the skw was partly cloudy, and the sun shone occasionally on the clusters. One 2007 cluster (A2) diminished somewhat through

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time because the colony was gradually moving dowm the arroyo, which is tyi^ical with the advance of winter (Calvert & Brower 1986). In 2008 the weather was clear throughout the experiment, and the clusters did not change in size during the course of the experiment.

Analyses. We performed statistical analyses with SPSS 14.0 (SPSS Inc.) separately for each year. Comparisons of the measurements inside and outside each cluster were made by one-tailed paired t-tests, wdth arcsin transformation of relative humiditv data, and the results were evaluated with a modified Bonferroni correction for multiple tests (Walsh 2004). Error bars used in the figures are 95% CM. about the means (±1.96 S.E.). Data from both vears were analyzed identically except that calibration of tlie hygrochrons for the 2008 measurements ensured that painvise comparisons of their readings were more accurate.

Results

2/5/08 2/5/08 2/6/08 2/6/08 2/6/08 2/6/08 2/7/08 2/7/08 2/7/08 2/7/08 12;00 18:00 0:00 6:00 12:00 18:00 0:00 6:00 12:00 18:00

date/time

Fig. 6. Recorcfs of (a) temperature and (h) relative humiditv Irom wdthin the eolony (average of three ambient hygrochrons) and from a clearing at the MBBR Field Station on the Llano de las Papas, Sierra Chincua, Vlichoacan, Mexico. The records Irom the clearing are given as recorded by both the Weather- Hawk weather station (WIT temperature only) and by a hy- grochron attached to the weather station (HY). Data were recordeil 5-7 Feb 2008 during three clear days. Tlie variation in temperature and BII is much less within tlie colonv than in the clearing, and the inverse relationsliip between temperature and Rll is apparent. Humidity in the clearing ranges from 100% during the night to a drying 27% during the day.

Weather. During the 2008 experiment, records from the nearby Chincua weather station (Fig. 6) revealed a much greater range in temperature and RH (from -3.2° to 17.8°C and 27% to 100%) than was recorded in and around the monarch clusters (±3.3° to 13.2°C and 33% to 89%), which were in dense forest and thus less exposed. With the absence of precipitation during the veiy clear three days of recording, data measured at the weather station showed temperature and relative humiditv to be inversely proportional (Fig. 6 a, b), as expected. Wind speed within the colony during our study gave five-minute averages up to 2.7 m/s, with gusts up to 3.8 m/s. Wind was highest during the afternoon, but even at night, wand was consistently more than 1.0 m/s.

2007 Experiment. Following the initial experiment in 2007, measurements of temperature and relative humiditv were analyzed without calibration, and the results suggested microclimatic buffering within the clusters. The inside of cluster A1 remained significantly warmer at night (t=6.491, df=49, p<0.001), although this night-time difference did not hold for cluster A2. The differences in RII at night were mixed. Microclimatic buflering was conspicuously greater, however, in the daytime. Both clusters remained significantly cooler inside than outside by up to 0.3°C (Fig. 7; cluster AT t=7.682, df=22, p<0.001; cluster A2: t=3.879, df=20, p=0.001). Coincidiug with lower temperatures, both clusters also maintained significantly higher humiditv inside (Fig. 8; cluster AT t=1.903, df=22, p=0.035; cluster A2: t=3.270, df=20, p=0.004). The separate ambient sensor (A3) recorded up to 0.7"C colder temperatures at night and morning than did the

Fig. 7. Differences in temperature across tlie clusters. The inside minus the outside temperature is shown, averaged over all readings for each separate cluster, with error bars indicating the 9.5% Cl for the means. The two 2007 clusters (initial experi- ment) are labeled A, and the five 2008 clusters are labeled B. In all cases, the inside of the clusters remained significantlv cooler than the outside during the dav (open bars), while 6 of tlie 7 clusters were significantly warmer at night (shaded bars).

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Journal of the Lepidopterists’ Societt'

sensors on the outside of the clusters, whereas it recorded up to 0.3°C wanner temperatures during the aftenroon and evening. Even though thermal buffering was greater inside the clusters, the outside of the clusters experienced slightly more moderate conditions than ambient temperatures closer to the forest floor.

2008 Experiment. Before analyzing the 2008 data, we calibrated the hygrochrons separately for warm and cold temperatures, with readings of one hygrochron adjusted to match the measurements from the lab tests of the other hygrochron. The precision of the temperature readings was higher than that of the relative humidity readings. Temperature adjustments for the five hygrochron pairs ranged from 0.06° to 0.11°C for warm (day) data and from 0.11° to 0.16°C for cold (night) data. Adjustments for relative humiditv^ ranged from 0.35% to 0.55% in warmth and from 0.93% to 1.07% in cold.

Using these calibrated measurements, the five clusters gave consistent results over the two days of

measurement (Figs. 7, 8). During the cold night hours, the inside of the clusters was significantly warmer than the outside for all five clusters (and six of the seven night measurements, with the seventh showing the same trend. Table 1). The difference between the inside and the outside declined during the long night hrs (Fig. 9). Three clusters (over four separate night comparisons; Table 1) had significantly higher RH inside despite the warmer temperatures, which would usually lead to lower RH. One cluster (Bl) recorded lower RH, while there was no difference in another (B4).

As with the 2007 results, microclimatic effects were stronger during the warm afternoon hours. During davtime, the inside of the clusters remained significantly cooler than the outside for all five clusters (and eight of the ten separate comparisons, with the other bvm showing the same trend. Fig. 8, Table 1). Also, the inside of the clusters maintained significantly higher RH than the outside for all five clusters (and nine of the ten separate comparisons, a response reciprocal to that of

Table 1. Statistical results of all 200S measurements, showing comparisons of the outside and inside readings of temperature and relative hnmiditv from each monarch cluster. The comparisons for each of the fi\'e clusters (Bl, B3, B4, B5, B6) have been sepa- rated for each day and each night in this tafile. Two davs and two nights were analyzed for each cluster, except for clusters B4-B6, for which data were a\ ailable for a single night. Analvsis bv paired t-tests was evaluated with modified Bonferroni correction for each set of comparisons.

Comparison

duster

date

location of highest readings

t^

Temperature

d.f

P

sig.

location of highest readings

Relative Humidity

h d-f

P

sig.

day/warm

Bl

6FebOS

outside

3.066

15

.008

«

inside

2.TT7

15

.014

Bl

7Feb08

outside

3.054

8

.016

inside

4.588

8

.002

B3

BFebOS

outside

5.139

15

.000

inside

4.5TT

15

.000

B3

TFebOS

outside

9.T02

8

.000

inside

4.135

8

.003

B4

6FebOS

outside

4.012

15

.001

inside

3.T95

15

.002

B4

TFebOS

outside

2.0T5

8

.0T2

n.s.

inside

3.243

8

.012

•

B5

6Feb08

outside

3.423

15

.004

<-

inside

1.808

15

.091

n.s.

B5

TFebOS

outside

2.135

8

.065

n.s.

inside

3.128

8

.014

-

B6

6Feb08

outside

4.T6S

15

.000

inside

4.802

15

.000

o

B6

TFebOS

outside

6.09T

8

.000

inside

4.302

8

.003

night/cold

Bl

6Feb08

inside

16.T49

2T

.000

outside

5.54T

27

.000

Bl

TFebOS

inside

T.346

2T

.000

outside

2.69T

27

.012

B3

6Feb08

inside

2.511

2T

.018

inside

3.888

27

.001

B3

TFebOS

inside

1.452

■27

.158

n.s.

inside

3.013

27

.006

o

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Fig. H. Differences in relative hnniiilitv across the clusters. The inside minus the outside RH is shown, averaged over all readings for each separate cluster, with error bars indicating the 95% Cl for the means. The two 2()07 clusters (initial experi- ment) are labeled A, and the five 2008 clusters are labeled B. In all cases, the inside of the clusters remained more humid than the outside during the day (open bars), while 4 of the 7 clusters were significantly more humid at night (shaded bars).

temperature (Fig. 9, Table 1). The sensons in the control bough (B7) averaged 0.1 3"C warmer during the 12 hrs of day and 0.1 1"C warmer during the 12 hrs of night than the outside ol the houshs with mouarchs. These small differences suggest that the conditions immediately outside of the clusters were accurate representations of the ambient conditions at the same height within the forest.

Dlscussion

The results found in 200(S support those suggested by the 2007 data: mouarchs on the inside of clusters experienced warmer temperatures at night, cooler temperatures during the day, and elevated relative humidity throughout both day and night.

The coldest temperatures occur during night and early morning hours, so these are the times when microclimatic bnffering against Ireezing comes into play. Significant buffering against cooler temperatures occurred throughout the 0000-0800 lir night period. Insulation against freezing would be most important for the butterflies in the clusters during the coldest moments, which occur when cloud cover opens up after winter storms and when cold air Hows through the colony. While a difference of 0.1° to 0.2°C will not substantially affect the probability of mouarchs freezing when they are diy, a combination of wetness and freezing temperatures during and immediately alter winter storms strongly lowers their suiwivorship (Anderson & Brower 1996; Brower cf al. 2004). Denser clusters, which frequently occur in years with larger

colonies, would likely increase the insulative effect.

Thermal buffering was stronger during daylight hours, with experimental clusters remaining cooler on the inside during peak warmth. Some variation exists among clusters because of different exposure to sunlight. The temperature differences are small, ranging up to 0.6°C; however, by lowering the warmest temperatures, these differentials may reduce metabolic rate by appro.ximately 6.4% and the consequent consumption of critically limited lipid reserves (.Vlasters et al. 19SS). We estimated the lipid savings by assuming: (1) the empirical relationship between body temperature and metabolic rate as measured for adult California monarchs (Chaplin & Wells 1982); (2) an average weight for an ovenvintering butterfly of 530 mg (Calvert & Lawton 1993); (3) a temperature reduction of 3.6 degree-hrs per day (ecjuivalent to 0.6°C for 6hr); (4) a 150 day ovenvintering period; and (5) the calm early Februar)' conditions under wliich this study was conducted. Witli these assumptions, the lipid savings for die ovenvintering season were small, ranging from 2 mg in a cold winter to 4 mg in a w^arm winter. These saxings are in context of the average lipids in November being 129 mg per butterfly (unpubl. data). However, as ambient temperatures rise in late Feliruan' and Alarch, tlie thermal insulation of the inside of clusters may increase and thus produce greater lipid savings. Also, even small savings could affect those monarchs that arrive low in lipids by providing them with critical energy that they need to fly to water and to remigrate at the end of the ovenvintering season. A savings of a few^ mg of lipids could have a significant effect on sunival.

time

Fig. 9. Temperature ditlerence between tlie inside and out- side of the clusters tlironsi;li the night ((.)()()()-( 1840 lirs). The in- side minus the outside temperature is shown, with error bars in- dicating the 95% Cl for the mean each hour; the data show the average difference for three measurements each hour (e.g., noon, ()020, and 0040 combined for 0020 hr) across all five 2008 clusters, with measurements recorded during 2 nights for clus- ters Bf and 15.3 and for 1 night lor clusters B4-B6 (n = 2f for eac h data point). The difference dc'creased by morning.

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Journal of the Lepidorterists’ Society

Relative lumiidity was higher hy up to 3% inside all clusters during the day and higher at night in most, despite the temperature also being higher on the inside. Increased humidity reduces the tl ireat of desiccation, an ever-present hazard wlien available moisture is limited, as is the case in the o\'envintering habitat as the dn- season progresses. Part of the elevated humidity could have been due to evaporative transpiration from the fir needles wthin the hntterdy clusters.

A greater range of temperature and relative humidity was found outside the clusters than inside. It is strikino; that structures as thin and seemingly delicate as butterfly wings provide insulation against emironmental fluctuations, but when manv wdugs are grouped together densely, as in the ovenvintering monarcii colonies, the reason becomes clear. Still air is such a highly elficient thermal insulator that most heat exchange occurs through convective air movement, ratlier than through conduction. The microclimatic buffering in butterfly clusters derives from their wings trapping pockets of aii' that remain still, an effect that may have been supplemented bv tlie fir bough needles. Single layers of butterflies sen^e as baffles that slow' cross-w'ise air movement, while dense, multilayer cinsters produce a quilt-like layer of insulation that blocks the convective exchange of heat between the ontsitle and inside of a cluster. This effect w'onld likely be even stronger during unstable w'eather wiien their wings also block winds.

Onr res\ilts are based on comparisons of temperature and relative humiditx' inside and immediately outside the monarch clusters, and, as such, they do uot distinguish potential microchmatic buffering provided by the fir needles from that created by the butterllies. It is likely, however, that the effect of the bough per se is less than the effect of the butterflies because most heat exchange is by convection, and air movement would be restricted more by a dense mass of butterfly wings than it would by an open bough of needles. The bulk of the microclimate differences inside and outside the clusters w'as likely from insulation produced by the densely packed butterflies, perhaps supplemented by buffering by the fir needles.

It is likely that the microclimatic advantages of cinstering are diminished by even moderate forest thinning that results in colder nights (Calvert et al. 1984) and veiy likely w'armer days. Unfortunately, illegal forest thinning, clear cutting, and burning of the clear cuts have become increasingly w'idespread in the Monarch Butterfly Biosphere Reseiwe (Brow'er et al. 2002; Ramirez et al. 2003, 2006; Honey-Roses & Calindo 2004; WAVF-Mexico 2006; Brow'er et al. 2008).

It is also likely that larger clusters provide greater

microclimate protection of the butterflies than smaller ones. During the 1990's, one of us (LPB) witnessed enormously dense clusters in the Cerro Pelon colony, but has uot seen such densities for several years. If tlie uuml)ers of mouarchs (wenHutering in Me.xico continue to decrease, as is suggested by data from the last 15 yr (Rendon-Salinas et al. 2008), the average densities and cluster sizes may diminish along w'ith a substantial measnre of the microclimatic advantages of clustering that we have demonstrated.

Conclusions

Onr results support the hyjrotheses that the clustering behavior of monarch butterflies on tree branches in their ovenvintering aggregations provides them with three microclimatic advantages, possibly enhanced by the fir boughs themselves: (1) bufferiug against lower temperatures during cold nights, thus lowering the probabilih' of the butterllies inside the clusters freezing; (2) buffering against heating during warm days, thus reducing the rate at whicli the internal monarchs consume their lipid stores; and (3) maintaining higher humiditv inside the clusters, thus lowering the rate of desiccation of the butterHies. While small, each of these factors contributes to a constellation of microclimatic advantages of cinstering.

This study took place nnder moderate weather conditions. When clearing follows wet winter storms, however, the temperature inside the forest can plunge to as low as -5°C (Calvert et al. 1983), which leads to extensive mortality (Brow'er et al. 2004). Had this experiment been done under these conditions, it is likely that the magnitude of the temperature differences inside and outside the clusters would have been greater. Likewise, the advantage of clustering in maintaining higher humidity wall most certainly be greater as the diy season advances and the weather becomes increasingly warm and diy.

The architecture of the short needled oyamel fir branches allows the butterflies to consolidate into larger and more dense bag-like clusters than possible on the flat needled cedars or the long needled pines (Figs. 2, 3). Because of the microclimatic advantages of cinstering on boughs, there may be competition among individuals to position themselves toward the center of the clusters. More detailed studies of cluster architecture, butterfly clustering beha\4or, and possible microclimate advantages enhanced by the tree species upon w'hich the butterflies form their cinsters are needed.

Acknowlei^gements

We tfiank Stuart Weiss for suggesting the use of iButton

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hygrochrons and I\an Liinon, Mia Magruder, and Carlos Carrillo Tellez for help in conducting the field experiments. VVe are grateful to Ing, Concepcion Mignel Martinez, Direc- tor of tlie Monarcli Butterfly Biospliere Reserve, tor facili- tating our access to the colonies and to the Arizmendi family lor providing accommodations in Angangueo. W'e are grate- Inl to Myron Zalncki and two anonymous reviewers for cri- tiques of the manuscript. We thank Jen Borton and Dong VV'eldon for discussion of the analyses and Tonya \7in Hook tor help with calibrating the hygrochrons. Diana Garland lielped with editing the digital color images, taken by Lin- coln Brower witli a Canon D-20 camera. We also thank Lighthawk, Inc., and pilots Clmck Scliroll and ]4a\id Knnkel for providing aerial reconnaissance allowing the photography of the monarch colonies. Finally, we thank fames Anderson lor insights into the design ol this experimental study. Sup- port was pnjvided by National Science Foumlation grant DEB-0415340 to Sweet Briar College, with Lincoln Brower and Linda Fink as principal investigators, the October Hill Foundation, and the Monarcli Butterflv Sanctnarv Founda- tion. Ernest Williams was supported by the Leonard C. Fer- guson Professorship Fund at Hamilton College. DGAPA-PA- PlIT (INI 14707) provided financial support to M. Isabel Ramirez.

Literature Cited

Anderson, J.B. & L.P. Brower. 1996. Freeze-protection of oveivvin- tering nionarch butteiHies in Mexico: critical role ol the forest as a blanket and an uinhrella. Ecol. Entoinol. 21: 107-1 16.

Brower, L.P. 1984. Chemical defence in hutterilies. Pp. 109-134 . lit R.I. Vane-Wright & PR. Ackeiy (eds.). The Biolo,g\' of Bntterllies. Academic Press, London.

. 1995. Understanding and misunderstanding the migration of

the monarch ImtterHy (Nymplialidae) in Nortli America: 1857-1995. J. Lepid. Soc. 49:’ 304-385.

. J.\(Z. Brower, & f.M. Corn ino. 1967. Plant poisons in a ter- restrial food chain. Proc. Nat. Acad. Sci. (USA) 57: 893-898.

& W.ll. Calvert. 1985. Foraging dynamics of liird predators

on ovenvintering monarch hiitteiHies in Mexico. Evolution 39: 852-868.

& L.S. Fink. 1985. A natural toxic defense system: cardenolides

in butterflies versus birds. Pp. 171-188 . hi N.S. Braveman & P Bronstein (eds.). Experimental Assessments and Clinical Appli- cations of Conditioned Food Aversions. New York Academy of Sciences, NY.

. B.E. Horner, M.M. Marty, C.M.Moffitt, & B. Viu,a-R.

1985. Mice {Perowijscus luaiiinilatiis lahecula. P. spicelegiis and Microhis mexicaiiwi) as predators of nionarch hutterilies (Daiiaus plexippus) in Mexico. Biotropica 17: 89-99.

, G. Castilleja, a. Peralta, ]. Lorez-Garcia, L. Bojorquez-

Tapia, S. Diaz, D. Melgarejo, & ,M. Missrie. 2002. (dnantitative changes in forest qualiW in a principal ovenvintering area of the monarch butterfly in Mexico: 1971 to 1999. Consen'. Biol. 16: 346-359.

, D.R. Ku,st, E. Rendon-Salinas, E.G. Serrano, K.R. Kust, ],

Miller, J.C. Fernandez del Rev, & K. Pape. 2004. Cata- strophic \\4nter storm mortality- of monarch hutterilies in Mexico during January 2002. Pp. 151-166. hi K.S. Oberliaiiser ami M.J. Solenskv (eds.). The Monarch Butterfly: Biology and Conserva- tion. Cornell University Press, Ithaca, NY.

, D.A. Slayback, & I. Ramirez. 2008. Alarming deforestation

revealed. Monarch Butterfly: Journey North Consemition News, 13 March 2008. Accessed .March 2008. http:/Avw\v.learner.org/jnortli/tm/monarch/Deforest_Ikonos2004_ 2008_MBSF.html

Calvert, W.II. & L.P. Brower. 1981. The importance of forest cover for the sunival of ovenvintering monarch hutterilies (Daiu/iis plexippus, Danaidae). |. Lepid. Soc. 35: 216-225.

& . 1986. The location of nionarch butterfly {Danuus

plexippus L.) ovenvintering colonies in Mexico in relation to topography and climate. |. Lepid. Soc. 40: 164-187.

, L.E. Hedrick, & iLP Brower. 1979. Mortality of the

monarch butterfly (Dimaus plexippus L.): avian predation at five ovenrintering sites in Mexico. Science 204: 847-851 .

& R.C). Lawton. 1993. Comparath-e phenology of wiriation in

size, weight, and water content of eastern North American monarch butterflies at five OA'envintering sites in Mexico. Pp. 299-.307 . lu S.B. Malcolm & .VI. P. Zalncki (eds.). Biology- ami Consenation of the Monarch Butterflv. Natural Histon' Museum of Los Angeles Countv, Los Angeles.

, W. ZuciiowSKi, & L.P. Brower. 1983. The effect of rain, snow,

and freezing temperatures on oven\'intering monarch butterflies in .Me.xico. Biotropica 15: 42 — 17.

, , & . 1984. Monarch hiitterlly eorisen'ation: inter- actions of cold weatlier, forest thinning and storms on the siinfA'al of OA'envintering monarcli butterflies (Daiuius plexippus L.) in Mexico. Atala 9: 2-6.

Chaplin, S.B. &P.I1. Wells. 1982. Energy resenes and metabolic ex- penditures of monarch hutterilies o\'en\'interirig in sontl iern Cal- ilornia. Ecol. Entoinol. 7: 249-256.

Clohdsley-Tiiompson, J.L. 1962. Microclimates and the ilistrihution ol terrestrial arthropods. Ann. Rca'. Entoinol. 7: 199-222.

Demrach, M. & B. Goeiilen. 1999. Aggregation, density ami longeATty correlate Avith humidity in first-instar iiA'inphs of the cockroach {Bliittella gennauicu L., Dictx'optera). J. Insect Physiol. 45: 423-429.

Fink, L.S. & L.P Broaver. 1981. Birds can OA'ercome the cardenolide defence of monarch huttei-flies in Mexico. Nature 291: 67-70.

, L.P. Brower, R.B. Waide, & PR. Spitzer. 1983. (.lAeiwTiiter-

ing monarch butterflies as food for insectiA'oroiis birds in Vlexico. Biotropica 15: 151-153.

Ga.airerale, (;. & B.S. TtiLLBERG. 1998. Aposematisrn and gregari- onsness: tlie cornhined effect of group size and coloration on sig- nal repellence. Proc. Roy. Soc. Pond. B 265: 889-894.

GRIN (Germplasm Resources Inform.ation Network). 2007. CiRIN Taxonomy for Plants. Taxon: Cupressus liuillei/i Klotsch ex End!., synonyun of Cupressus lusiliiuica Mill. Aar. lusiUmica. Agri- cnltnral Research Sen ice, United Stated Department of Agricul- ture. Accessed NoA'ember 2007. http:/AAAAAV.ars-grin.gov/cgi- hin/npgs/htmPtaxon.pl?12657

Glendinning, J.I. & L.P. Broaver. 1990. Feeiling and breeding re- .sponses ol five mice species to oA'en\'intering aggregations of the monarch butterfly. [. Aniin. Ecol. 59: 1091-1 1 12.

IIa.MILTiyn, VV.D. 197i. Geometiy lor the selfish herd. j. Tlieoret. Biol. 31:295-311.

Honey-Roses, [. & C. Galindo. 2004. Illegal logging and its impact in tlie Vionarch Butterfly Biosphere Resen'e. Report, World Wildlife Fuml-Mexico, Mexico City, Mexico.

INEGI (Instituto Nacional de Estadistica Geografi.a e Infor- matica). 1999. Carta Topografica, Angangueo, E14A26, Me.xico y .Vlichoacan, Escala 1:50,000, Segunda Edicion, Mexico City .Mex- ico.

Malcolm, S.B., B.J. C(.k:krell, & L.P. Brow er. 1993. Spring recolo- nization of eastern Nortli America by the nionarch butterfly: suc- cessive brood or single SAA'eep migration? Pp. 253-267 . lu S.B. Malcolm & M.P Zalncki (eds.), Biologv' and Consenation of the .Monarch Butterflv. Natural Histon' Museum of Los Angeles County, Los Angeles.

M asters, A.R., S.B. Malcolm, & L.P Brower. 1988. Vionarch but- terfly (Diniaus plexi]ii>us) thermoregulaton' hehaA ior and adapta- tions for ovenA'intering in Mexico. Ecology 69: 458-467.

.VIissRiE, VI. 2004. Design and implementation of a new protected area for OA'en\dntering monarch bnttc'rflies in Mexico. Pp. 141-150 . In K.S. Oherliauser & M.J. Solenskw (eds.). The Monarch Butterfly Biology and Consenation. Cornell IhiiA-ersitv Press. Ithaca, NY.

PoUGlI. FIT 1988. Vliniicn' of vertebrates: are the rules different? Amer. Nat. 131: S67-S102.

Ramirez, VI. I. , J.G. Azcarate, & L. Luna. 2003. Effects ol human ac-

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Journal the Lepidopterists’ Societt'

tivities on monarch liutterH\- habitat in protected mountain lorests, Mexico. Forestry Chron. 79: 242-246.

. Iv MiR.'tNDA, & R. ZuBiETA. 2006. Serie Cartografica Monarca,

Vohmien 1 , Vegetacion y Ciihiertas del Suelo, 2006, Reserva de la Biosiera Mariposa Monarca, Mexico. Instituto de Geografia, Uni- versidad Nacional Autononia de Mexico, Mexico City, Mexico.

Rendon-Salinas, E., S. Rodi!iguez-Meii'a, M. Cruz-Pina, & C. C;alindo-Leal. 2007. Monitoreo de las Colonias de Hibeniacion lie Mariposa Monarca: Superficie Forestal de Ocupacion en Di- ciembre de 2006. World Wildlife Fund-Mexico, Me.xico City, Mexico. Accessed January 200<S. http://www.vv\vl.org. mx/\v\vtmex/publicaciones.plip?tipo=reps&p=bm

, N. Acevedo-Hernandez, S. Rodriguez-Meji'a, tk C.

(Pu.indo-Leal. 2008. Monitoreo de las colonias de hibeniacion de mariposa monarca: Superficie forestal de ocupacion en Di- ciembre de 2007. Monitoring ot the 2007-2008 oveiAvintering season. World Wildlife Fund-Mexico, Mexico City, Mexico. Ac- cessed April 2008. !ittp:/Av\v\v.\vwf.org.nix/vvwfmex/ de.scargas/rep_monitoreo_colonias_nionarca_07-08.pdf

Seiber, J.N., L.P Brower, S.M. Lee, M.M. McChesnev, Il.T.A. Cheung, C.J. Nelson, & T.R. Watson. 1986. Cardenolide con- nection between oyenvintering monarch butterflies Irom M exico and their larval foodplant, Aaclcpia.s syriaca. J. Chein. Ecol. 12: 1157-1170.

Sili.en-Tullberg, B. & O. Leimar, 1988. The evolution of gregari- ousness in distasteful insects as a defense against predators. Amer. Nat. 132: 723-734.

SiMRSON, R.G. & C.Fi. Welborn. 1975. Aggregations of Altalla wee- \'ils, Hi/pera j)ostica. Convergent lady beetles, Hippodainia con- wrgcn.s, and other insects. Environm. Entoniol. 4: 19.3-194.

Slayback, D.A. & L.P. Brower. 2007. Further aerial surveys confirm the extreme localization of overwintering monarch butterfly colonies in Mexico. American Entomologist 53: 146-149.

, L.P. Brower, M.I. Ramirez, & L.S. Fink. 2007. Establishing

the presence and absence of overwintering colonies of the monarch butterfly in Mexico by the use of small aircraft. Amer. Entomol. 53: 28-39.

Waldbauer, G. 2000. Millions of monarchs, bund les of beetles. Har- vard University Press, Cambridge, MA. 272pp.

Walsh, B. 2004. Multiple comparisons: Bonferroni corrections and false discovery rates. Accessed November 2007. http://nitro.bio.sci.arizona.edu/workshops/Aarhus2006/pdts/Multi- ple.pdf

White, D., K.C. Kendall, & II.D. Picton. 1998. Seasonal occur- rence, body composition, and migration potential of army cut- worm moths in northwest Montana. Canad. J. Zool. 76: 835-842.

WAVF-Mexico. 2006. Forest loss and deterioration in the monarch buttei-fly Biosphere Reserve, 2005-2006. World Wildlile FuncL Mexico, Me.xico City, Me.xico. Accessed November 2007. htt]')://www. wwl.org. m.x/wwhnex/descarga.s/06 10_Inlorme_monarc a0506_english.pdf

Yoder, J.A., 11.11. Hobbs, & M.C. Hazelton. 2002. Aggregate pro- tection against dehydration in adult females of the cave cricket, Uadenoccus cumhcrlandicus (Orthoptera, Rhaphidophoridae). J. Cave Karst Stud. 64: 140-144.

Received for piddication 6 ]un 2008; revised and accepted

12 Sep 2008

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62(4),2()()8.189-200

COMPARATIVE SUCCESS OF MONARCH BUTTERFLY MICRATION TO OVERWINTERING SITES IN MEXICO FROM INLAND AND COASTAL SITES IN VIRGINIA

Larry J. Brindza,

9701 Ilurr Court, Burke, VA 22015

Lincoln P. Brower,

Department of Biology, Sweet Briar College, Sweet Briar, VA 24595; email: lirower@,sbc.edu

Andrew K. Davis,

Warnell School of Fore.stry and Natural Resources, University of Ceorgia, Athens GA 30602

AND

Tonya Van Hook

Department of Biolfjgy, Sweet Briar College, Sweet Briar, VA 24595

ABSTRACT. Prior tagging studies at Atlantic coastal sites in New Jersey and Virginia suggested that fall migrant monarch Butterflies (Danaus plexippus L., Nymphalidae; Dauainae) of the eastern North American population have lower recovery rates at ovenvintering sites in Mexico compared to the overall recoveiw rates reported Bv Monarch Watch for monarchs tagged throughout the late summer Breeding range. Here we present the results of the first quantitative study that compares the proBahility of recapture in Mexico of monarchs tagged at coastal sites watli inland sites that are east of the Appalachian VIountains. During the 2()()l-2()06 fall migrations, we tagged 1 ,008 monarchs along the Appalachian piedmont in Virginia, of which 13 (1.29%) were recovered in Mexico. In contrast, out of 1,216 tagged at Atlantic coastal locations in Virginia, only 2 (0.16%) were recovered. This eightfold lower recapture rate of the coastal monarchs is highly significant. The data also indicated that mf)narchs migrating along the piedmont on the eastern side of the Appalachians are nearly as likely to reach Me.xico as are those that migrate west of the Appalachians. We conclude that migrating along the Atlantic coast per se is more riskw than migrating inland either east or west of the Appalachians. The recovery data also determined that Both sexes of the piedmont migrants reached Mexico, But, tor unknown reasons, fe- males were more successful. Since coastal migration occurs regularlv and involves veiy large mmiBers of monarchs, the Atlantic coast is not an aberrant migratory route as the Urquharts maintained. Why then do fewer coastal migrants reach Mexico? Some continue southward and may become incoiporated in and help sustain Breeding populations in soutli Florida, Cuba and perliaps in other Caribbean islands and the Yucatan. To explore other possible reasons for the lower success of coastal monarchs in reaching Mexico, we compared wing lengths and wet masses of 483 inland with more than 140 coastal monarchs. The latter had slightiv but significantly smaller wing lengths and, even after accounting for variation in wing length, they weigheil less than the inland monarchs. The lower wet mass reflects lower lipid and/or lower water contents which we argue may be a consequence of anthropogenic degradation of much of the native flora and nectar sources along the Atlantic coast. W'e con- sider various hyjrotheses that may account for the coastal migrants' smaller wings than the inland migrants, including the controversial idea that the longer winged migrants may lie blown out to sea.

Additional key words: tagging and recapture rates, wet mass, wing length, nectar availability'; Atlantic coastal eco.system deterioration, liskw fall migration route.

Qualitative knowledge derived from the recoveries of tagged fall migrant monarch butterflies {Danaus plexippus, L.) has indicated that their success in reaching the overwintering areas in Mexico is substantially greater when the butterflies are tagged west comjrared to those tagged east of the Appalachian Mountains (Urejuhart & Urquhart 1979a, b; Unjuhart 1987; Monarch Watch 2006). An unexplored aspect of this difference is whether monarchs migrating along the Atlantic coast per se have a lower probabilit)' of reaching Mexico, or whether all monarchs mieratino; east of the Appalachians, including the piedmont and the coastal areas, are less successful.

To obtain (jnantitative data on the fall migration along

the Atlantic coast, Walton (1999), Walton & Brower (1999) and collaborators initiated a tagging program in Cape May Point, New Jersey. In the fall of 1998, they tagged 7,541 monarchs (number corrected by Brower ct al. in prep), of which seven were subsequently found at the Mexico ovenvintering sites, a recapture fre(jnency of 0.093%. In 1998 Garland & Davis (2002) started a second coastal tagging program on the southern tip of the Dehnarva Peninsula in Virginia. They released 2,190 monarchs over three years (1998-2000), of which one was found in Mexico, a recapture frecjnency of 0.046%. In contrast, of an estimated 1.1 million monarchs tagged by Monarch Watch participants from 1992 through 2006 in the eastern US and southern

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Journal of the Leridopterists’ Societt'

Canada, 12,()()() to 14, ()()() were recaptured in Mexico, a recoveiy rate of 1.09% to 1.27%i (Taylor pers. coin. 2007; Monarch Watcli 2006). Using Monarch Watch's lowest recoveiw rate as a rough estimate of the overall eastern rate and dividing it hy each of the above coastal rates (1.09% / 0.093%. = 1L7; and 1.09%. / 0.046%) = 23.7) indicates that tlie coastal inonarchs have only 1/1 2th to l/24th of the chance of being recaptured in Mexico (see also Taylor, in McNeil 2006).

This nnich lower prohabilitv of coastal inonarchs reaching Mexico raises four questions that we address in this paper. First, are all inonarchs that migrate along the eastern side of the Appalachians less likely to reach Mexico than inonarchs that migrate west of the Appalachians? Or, second, do those inonarchs that migrate along the piedmont that stretches eastwards from the Appalachians to the coastal plain (Atwood 1940; Raisz 1957) have a success rate similar to migrants west of the Appalacliians? Third, if the coastal migrants per se are less successful, do these inonarchs exhibit differences in physical properties from the inland piedmont migrants? Fourth, if there are physical differences between the coastal and inland piedmont

inonarchs, what factors might account for the differences?

To answer the first two questions, we compared the nnmber of recaptures in Mexico of inonarchs collected and tagged along the eastern edge of the Appalachian piedmont in northern Virginia with recaptures of inonarchs collectetl and tagged during the same years along the Atlantic coast in southern Virginia. We addressed the third question by comparing wing lengths and adult weights (wet mass) of snb-samples of the tagged inland and coastal inonarchs. We addressed the fourth question by relating the wing length findings to greater coastal losses due to wind and possible other causes, and by relating the wet mass findings to anthropogenic changes in habitat quality along the Atlantic coast.

Materials and Methods

Collecting sites. Over six years (2()()l-2()06) betw'een the last week of August and the last week of Octolier, Brindza collected fall migrant inonarchs from one or more coastal and inland sites in Virginia. The collection dates overlapped with the timing of the fall

Fig. 1. Location of coastal and inland study sites in eastern \drginia and average wet masses of fall migrant monarchs in eastern North America. The coastal sites were located on the southern tip of the Delmawa Peninsula (small square in the lower inset box). The inland sites were centered around the town of VVoodbridge on the piedmont of the Appalachians (small circle in the lower in- set box). The numbers on the map indicate average wet masses (mg) of males and females combined of fall migrant monarchs from this study and from other published studies (Brown and Chippendale 1974; Gibo and McCurdy 1993; Borland et al. 2004). The up- per left inset shows the appro.ximate range of the eastern North American monarch population, with the location of theMexican oveiAvintering area.

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191

migration along botli the Atlantic coast in Virginia (Garland & Davis 2002; Gihhs et al. 2006) and through an inland site on the eastern edge of the Bine Ridge Mountains at Sweet Briar Gollege, Virginia, about 275 km west of the coastal area (Brower et aJ. 2006). In the fall of 2001, Brindza concentrated on tagging the butterflies and, from 2002 through 2006, he also weighed and measured the forewing lengths ol sub- samples of those that he tagged and released.

The coastal samples were collected at Kiptopeke State Park, on the Eastern Shore of Virginia National Wildlife Refuge and Fisherman Island National Wildlife Refuge. These areas are surrounded to the west by Ghesapeake Bay and to the east and south by the Atlantic Ocean (Fig. 1). Both are good locations for capturing migrating monarchs because of the tunneling effect of the peninsula (Garland & Davis 2002).

The inland monarchs were collected along the Piedmont about 190 km northwest of the coastal area within a 10 km radius of Woodbridge, VA (3S" 3S' OS" N, 77“ 15' 44"W), 20-30 km SW of Washington. D.G. (Fig 1.). The collecting site in 2001 was solely in fjorton, while from 2002-2006, the butterflies were collected in Forton, Gunston Gove, the Occo(|uan Bav National Wildlife Refuge and Mason Neck State Park.

Collecting methods. Brindza netted most monarchs while they were nectaring on several species of composites growing in open fields or in flowerbeds, and on cultivated and native shrubs. About 2% were collected from roosts. Immediately after capture, he removed each monarch from the net and placed it in a 5.1 X 7.6 cm glassine envelope. Successive captures were accumulated for about 10 minutes in a small plastic bo.x and kept out of direct sunlight.

Brindza made all plant identifications based on Newcomb (1977), Peterson & McKennv (1968) and Fobstein (1990). We followed the USDA plant data

base to standardize the common and scientific nomenclature (Anon. 2007a). Gomposites (A.steraceae), on which many butterflies were nectaring, incinded bearded beggar ticks {Bidens aristosa (Michx.) Britt.), woodland sunflower {HelUmthus divaricatus L.), bull thistle {Cdrsiiiin viilgare (Savi) Ten.), other thistles {Cdrsiiiin spp.), false boneset (BrickeUia eupatorioidcs [L.] Shinners), white snakeroot (Eupatoiiiun nigosii)}) = Ageratina alfissima (F.) King & H.E. Robins), seaside goldenrod (Scdidago seuipcrvirois F.), Solidago spp., hyssopleaf thoroughwort {Eiipatoriiim hijssopifolhnn F.), late flowering thoroughwort {Eiipatoriinn serotiiium Michx.), orange cosmos (Cosmos stilj)luirctis Gav.) and garden cosmos (C. hipimiatiis Gav.). The shrubs on which they were nectaring included butterlly bush (Biiddleia davidii f^., Buddleiaceae), Russian olive (Edacagnus angiistifolia F., Elaeagnaceae), abelia (Ahclia ahelia R. Br., Gaprifoliaceae), lantana, (Eaiitdiia camara L., Verbenaceae) and groundsel tree (eastern baccharis, Baccharis halimifoUa F., Asteraceae).

Tagging. Brindza tagged the butterflies within fO minutes of capture using nnmbered adhesive tags pro\’ided by Monarch Wkitch. 0\er the six years, he tagged and released 1,216 monarchs in the coastal sites and 1,008 in the inland sites (Table 1). We subsequently determined those recox ered at the ox'enx'intering sites in Mexico by consulting the Monarch Watch tag recox'eiv data base (http:/A\a\'\\xmonarchwatch. cf ) m/tagm ig/ rec( )ve I'ies . h t m ) .

Weighing and measuring. lOuring 2002-2006, Brindza measured the left forewing length and wet mass of snb-samples of the monarchs that he tagged (Figure 2). He measured left forexx'ing length follo\\4ng the protocol of Brewer & Van Hook (in prep.). This measures (mm) the straight line distance on the x'entral surface of the forewing from the forewing tip to the xx'hite dot on the base of the \\4ng xxdiere the xx'ing

Table 1. Summarv ot tlie number of moiuircli butlterllies tagged during tlii.s .stiidx' at coastal and inland sites in Vrginia.

Year

Coastal

Inland

Grand Total

Males

Females

Total

% Female

.Males

Female.s

Total

% F'emale

20t)l

231

182

413

44.1

.374

151

525

28.8

938

2002

67

18

85

21.2

41

22

6.3

.34.9

148

200.3

34

20

54

37.0

35

21

56

37.5

no

2004

7

4

11

36.4

2

0

2

0.0

13

200,5

14

17

31

.54.8

99

64

163

39.3

194

2006

370

252

622

40.5

134

65

199

.32.7

821

Total Tagged

723

493

1216

40.5

68.5

.323

1008

,32.0

2224

192

Journal of the Leriooptehists’ Societt'

Fic:. 2. Dislrihution oi (A) lorewing lengths (niin) and (B) wet masses (mg) oi the coastal and inland monarclLS.

A.

52.8

^ 52 4 E

^ 52.0 sz

O) 51.6

c

CD

-I 51.2 CD)

^ 50.8 50 4

50.0

B.

600 ^ 580

O)

E 560

540

CD

^ 520

480

460

440

W Inland M Coastal

2002 2003 2005 2006

Fig. 3, (A) Average \\'ing length and (B) average wet mass of monarchs for the four years (2002-2(K)6, e.xcluding 2004) for both inlaml and coastal sites. Bars indicate 9.5% confidence in- temils.

attaches to the thorax. All measurements were made to the nearest 0.1 mm with handheld Mitutoyo digital calipers (Ben Meadows Co., Janesville, VVI). Brindza also measured wet mass, rounded to the nearest mg, using a portable electronic balance with an accuracy of 0.001 g (Acculah, Model PP2060D, Sartorius Group, Gottingen, Germany). The balance was recalibrated on each day of use. Throughovit the study, the length of time between capture and measuring and weighing individual monarchs did not exceed 15 minutes. Weighing tliem as soon as possible after capture is imperative to avoid mass (weight) loss through desiccation.

Stati.stical analyses. We used Statistica 6.1 software (Statistica 2003) for our analyses. We used chi-square to test for significant differences in the nnmbers of recaptures in Mexico of monarchs tagged at the inland vs the coastal sites. We also used chi-scpiare to test for differences in the numbers of tagged males and females in reaching Mexico. We used ANOVA to e.xplore the factors inffueuciug variation in monarch wing lengths and wet masses. With wing length or wet mass as the dependent variable, we included site (inland and coastal), sex (male and female), and year (2002, 2003, 2005 and 2006) as categorical independent variables. The 2004 data were excluded from the analyses because of tlie veiy small sample sizes. All two-way and three- way interactions were initially included in the model, and dropped if not significant. We used analysis of covariance to examine the factors affecting monarch mass, v\4th wing length as a covariate to account for the fact that mass is influenced by butterfly size {i.e. forewTug length).

Results

Recaptures in Mexico. Thirteen of the 1,008 (1.29%) butterflies tagged at the inland sites were recaptured while only 2 of 1,216 (0.16%) were recaptured from the coastal sites (Tables 1 and 3). This eight-fold difference in recapture rate is statistically significant (chi-square = 10.41, 1 df, P < 0.001). Our data thus indicate that monarchs migrating inland across the piedmont east of the Appalachians have a much higher probability of being recaptured in Alexico than do those nrigrating along the Atlantic coast.

Our low coastal recapture rate was l.S times higher than that found by Walton & Brower (1999) in Gape May (0.093%) and 3.6 times higher than that found by Garland and Davis (2002), on the southern tip of the Delmarva Peninsula in Virginia (0.046%). Our higher value is likely due to the fact that the majority of our monarchs were tagged during the fall preceding the Januaiy 2002 storm that killed nearly one quarter of a

Volume 62, Number 4

193

billion monarchs in two colonies (Brower ef aJ. 2004) and resulted in an all time high tag recoveiy rate in Mexico (Monarch Watch 2006).

There was a deficiency of females each year in all samples except for the coastal sample in 2005 (Table 1 ). For the inland samples tagged in 2001, there were 374 males and 151 females, i.e. 29% females. Of the 12 inland monarchs recaptured in Mexico that season, 7 of 12, i.e. 58% were females. Tims there was a reversal in the sex ratio with twice the frequency of tagged females recaptured (chi-square = 5.12, 1 d.f., P < 0.025) indicating that both sexes reached Mexico from the inland route, but that females were substantially more successful than males in doing so.

Wing length. The data for the coastal and inland samples are shown in Figs. 2A and 3A. Two way ANOVA (Figure 4) analyzed differences for site, year and sex for the 617 monarchs that we measured. We found no significant (P > 0.10) two-way interaction terms. When these were dropped, the main effects revealed significant effects of both year (F^gjj = 10.5, p<0.001) and site (F^pjj=4.0, p=0.046). Tnkey’s post- hoc comparisons indicated that monarchs captured in 2002 were significantly smaller than in all other years. The ellect ol site is evident in Figure 3A, with monarchs slightly but significantly larger at the inland sites on average and for three of the four years. At the inland sites, the average for both sexes was 52.1 mm, while at coastal sites it was 51.3 mm, a difference of about 1.5%.

Body mass. The data for the coastal and inland samples are shown in Figs. 2B and 3B. For wet body mass, the final model contained several highly

II

^ 5

Inland Coastal Monarchs Monarchs

o) 15

r 10

CO

^ 0 a:

Vi Vi <0

■10 ■i c

Fig. 4. Conipari.son of average residual mass (residuals from a linear regression of mass versus wing lengtli) of monarchs from both inland and coastal sites. The difference is significant (t-test, df=62.5, t=2.31, p=0.021). Bars indicate 9.5% confidence intervals.

significant main effects and interaction terms (Table 5), most notably, the main effects of year (F3^,n„=S.6, p<0.()01), sex (Fjg||,=4.4, p<().037), and wing length (Fj gg,,=lS2.5, p<().()()l). Males weighed significantly more than females (Table 2B), 552 mg vs 511 mg overall), and not surprisingly, the effect of wing length was positive (i.e. monarchs with longer wings also had greater mass). There was a significant interaction of site“year (Fggg„=5.7, p=().001. Table 5). This interaction effect is evident in Fig. 3B, in that the monarchs from the coastal site weighed less than those from the inland, but the magnitude of this effect depended on tlie year, being smaller in 2006 than in 2002. Further, the difference in wet mass between sites was not due to the size difference in monarchs, as indicated by an analysis of covariance in which the effect of wing size was included in the mass model. To elucidate this point further, we plotted (Fig. 4) the average residual mass (from the significant linear regression of mass versus wing length) of both sites so that the difference in weights, after wing length is accounted for, can be seen. Thus when size is removed, the difference in mean residual mass between sites is significant (t-test, df = 625, t= 2.31, p = 0.021). Thus the average wet mass of the coastal migrants (496 mg) was 9.6% less than the inland migrants (.549 mg) and was lower than that found in several other studies (Brown & Chippendale 1974; Gibo & McCurdy 1993; Borland et al. 2004) as shown in Figure 1.

Discussion

The data from this study in Virginia demonstrate that monarchs captured during the fall migration along the Atlantic coast differed in three significant ways from those migrating inland across the piedmont between the Appalachians and the coast. Relatively few of the coastal migrants succeeded in reaching the oveiAvintering sites in Mexico, they had slightly smaller wing lengths and they had lower wet masses. These results have major implications for a more complete understanding of the fall migration of the eastern North American population of the monarch butterfly.

Migration east and west of the Appalachians.

Based on their tagging studies, Urquhart & Urqnhart (1979a, b) and Urqnhart (1987) maintained that monarch migration along the Atlantic coast is "aberrant". Briefly, they contended that variable munbers of fall migrants are blown by westerly winds over the Appalachians to the east coast. They reasoned that these avoid flying over the ocean with most continuing to migrate south along the coast into Florida and thence into the Caribbean, without reaching the oveiwintering sites in Mexico. The Ur(|uharts' aberrant

194

Journal of the Lepidopterists’ Society

migration hypothesis, together with the much low'er frequencies of recaptures in Mexico of mouarchs tagged east compared to those tagged w'est of the Appalachians liy Monarch Watch (Taylor pers. comm.. 2007; Monarch Watch 2006), has led to the general assumption that monarch migration anv\\4iere east of the Appalachians is a less successful strategy in reaching Mexico. This contention wtis reinforced by an analysis of 40 years of recapture data (Rogg ct al. 1999) showTug that migrants west of the Appalachians likely do get hkmm eastyvards, but they are in some yvay able to compensate tor this yyand drift and, as some birds and dragonflies do (Richardson 1990; Svrgley 2004), they' reorient to a sontliyy^esterly course leading them to Mexico (see also Iloyvard 2007).

Based on the results of our study', this general model requires modification. W'e have determined that migration east of the Appalachians along the piedmont mav be as snccessinl as the migration yvest of the .'Appalachians. In contrast, as maintained in the past and

as yve have confirmed, migration along the coast perse is tar less successful, flowever, being less successful does not necessarily mean that the coastal migration is aberrant, a descriptor that we consider misleading.

Rejection of the aberrant migration hyjjothesis. In contesting the aberrant coastal migration hy|)othesis, Walton & Broyy'er (1996, 1999) reported that at least some tagged coastal mouarchs do succeed in making it to Alexico, as yve have again shoyy'ii in this paper. Walton & Broyy'er also reemphasized that the coastal migration has occurred regularly since it yvas described in the 19th centui'v and often iny'oh'es spectacular numbers of butterflies (Broyy'er 1995). This has been confirmed (|uantitatively by fifteen consecutive annual censuses in Cape May, Neyv Jersey begun in 1991 (Walton & Broyy'er 1996; W'alton et al. 2005) and by nine annual coastal censuses in Chincoteague, Virginia, 117 km south of Cape May (Gibbs et al. 2006). Further eyidence of the large magnitude of the coastal migration includes reports of nocturnal roosts of over 10,000

T.yiiLE 2, A. Female anil male mean mass (wet weight) anil size (\vin« length) comparisons

behveen Coastal and In

land collections sites

in

\’A. 2()02-2()06. B.

Oi erall mean mass anil size comirarisons:

1) Coastal versus

Inland, combining all years

and sexes and 2) male versus

lemale combining all y'ears and both

Coastal and Inland sites.

Data for 2004 are not included because of veiv small

sample sizes.

A.

WET \t’ElCHT(mg)

WING LENCTIl(mm)

Females

Males

Females

Males

Year

Coastal

Inland

Coastal

Inland

Coastal

Inland

Coastal Inland

2002

Mean

449

557

524

593

49.9

.50.7

51.3

50.9

STD

49.7

83.3

.54.4

68,1

2.3

2.1

2 7

2.1

N

14

22

31

41

14

22

34

41

200:3

Mean

495

539

483

585

52.1

51.9

51.1

52.3

STD

59.8

65

I i

88.4

1.4

1.1

2.0

1.9

N

15

21

27

35

15

21

27

35

2005

Mean

487

507

492

561

52

51.8

50.9

,52.6

STD

S4.6

95.9

93

88.2

2.2

2.5

2.4

1.9

N

17

64

14

99

17

64

14

99

2006

Mean

521

514

516

554

.52.3

52.3

51.8

.52.5

STIY

43.2

t 1

72.7

73.8

1.7

2.1

0,9

2.0

N

6

65

9

1.34

6

65

9

134

B

WET WEIGHT (mg)

WING LENGTII(mm)

Coastal

Inland

Coastal

Inland

1 . All Yrs &

Mean

496

549

51.3

,52.1

Both Sites

STD

71.4

85

2.2

2.1

N

133

481

136

481

Females

Males

Females

Males

2. All Yrs &

Mean

511

552

51.8

52.1

Both Sexes

STD

82.8

82.8

2.2

2.1

N

224

390

224

393

Volume 62. Number 4

195

iiionarchs on Cliincoteague (Gibhs pars, coinni.) and on Cape May (Smith 2007).

Given the fact that the Atlantic coastal migration is an integral part of the monarch's fall migration, what is the fate of migrants of the eastern North American population that do not make it to Alexico? Cardenolide fingei'printing indicated that some migrate into south Florida where they become incorporated into local breeding populations on the eastern edge of the Everglades (Knight 1998). Cardenolide fingeqorinting together with isotope marker analyses determined that still others continue across the Caribbean to Cuba where they also liecome incoiporated into local breeding populations (Dockx et al. 2004). Those that may reach tlie Yucatan or any of the Antillean islands (Urquhart 1987) may help sustain these tropical populations. However, the ability of all these butterflies to remigrate northwards the following spring is nil because, in becoming reproductive under the high tropical temperatures, they lose their migratoiy capacity' and will not l)e aide to live for the five or more months until spring arrives along the Gulf Coast (Brower 1995; Zemaitis 2005). On the other hand, some of those coastal migrants that regain the southwesterly migratoiy track do make it to the Mexican ovenvintering sites and have the opportunitv to remigrate back into the southern USA the following spring.

In light (d all these recent findings, we reject the aberrant migration hvpothesis and we cannot agree with Taylor's contention (in McNeil Jr. 2006) that monarchs migrating along the coast are "toast." However, the lower recapture rates, shorter wing lengths and lower wet masses of the coastal migrants do indicate that there are negative factors affecting these monarchs' ability to reach Mexico, What might these negative factors be?

Risk of being l>lown out to sea favors shorter wing lengths. When one considers the distances tlie monarchs may fly, coastal migrants must be severely challenged by winds. The Atlantic coastal habitat extends for 2,700 miles from Maine to Florida, includes the Florida Gulf Coast, and continues westward and southward to the border of Texas and Mexico (Beatley et al. 2002). We propose that monarchs migrating along the coast have shorter wng lengths than those migrating inland because the larger individuals are more likely to get blovwi out to sea and have more difficulty fl)4ng back- in than do the smaller ones. We are not advocating the idea that the coastal migrants are a sub-population that has been selected for shorter wing lengths. In fact, the likelihood of shorter wings geneticallv evolving is unlikely because of the random mating that occurs among the millions of individuals of the eastern population that takes place in Mexico (Brower f995).

However, it is relevant to point out tliat natural selection is a strong evolutionaiw force that has shaped the flight dynamics of both birds and insects along coastal environments, and, on oceanic islands, has led to flightlessness in many lineages. ft is also well established that insects lose control of their direction and velocity when they fly up out of the slower mo\ ing air in the Iroundaiy layer near the ground and can be carried away by the wind (pp. 298, 324, in Dudley 2()0(); Alexander 2002). However, Robert Dudley (pers. comm.), contends that the opposite slumld be true, namely that the larger winged indi\4duals should have a bettei' chance of fighting their way back in from the ocean to the coast. Dudley & Syrgley (2008) also found that several neotropical migrant butterflies reduce their flight speed as their lipitl resei-ves deplete. Thus, there may be an inteqrlay between size and mass in the cfjastal monarchs, resulting in the larger individuals that have a depleted lipid mass ha\ ing to slow down, and therefore lowering their abiliW to fight the wind.

While we have no direct evidence, our wing length hxqrothesis is consistent with obsenxitious made by Schmidt-Koenig (1993) along the Atlantic coastline that monarchs avoid fl)4ng over large bodies of water unless the direction and speed of the winds are favorable. Gibbs (2007) also obsen ed monarchs' strong reluctance to lly southwesterly across the Chesapeake Bay when the winds were unfavorable. Tliat migrating monarchs are sensitive to unfavorable winds is also evident from their response to cross-winds by ll)ing low to the ground (Schmidt-Koenig 1985; Davis & Garland 2002; Garland & Davis 2002), or by simply pausing their migration to wait for better conditions to resume fl)iug and soaring (Schmidt-Koenig 1985; Davis & Garland 2004). fshii et al. (1992), working along the Gulf Coast south of Tallahassee, Florida, counted the numbers of fall migrants that were flying over the ocean and found that the number Hying inland exceeded the number living out. They inteipreted this as evidence for reluctance to sustain Hight across tlie Gulf

Energetically contending with the coastal environment. One hypothesis to e.xplain the lovv'er w'et mass of the coastal monarchs compared with those collected inland is that excess exertion burns their lipids while they confront uufav'orable beach winds and cross large bodies of water, including the numerous bays and sounds along the coast. Gibbs (in Gibbs et al. 2006; Gibbs 2007, pers. comm.) has studied coastal monarch migration through Chincoteague in Northern \irginia for 14 years (1994-2007) and she has frequently obseived large numbers of monarchs being Ivlowai out to sea and others struggling against winds to return to land. She also noted that the butterflies tliat succeeded in

196

Journal of the Leridorterists’ Society

Table 3. Fifteen recoveries in Mexico of tlie 2,224 monarchs tagged Iry L. Brindza at inland and coastal sites in Virginia over five years (2001-2()06). The tag cities are the towns closest to tlie tagging locations.

Sex

Tag Code

Tag City

Tag Date

Report Date

Wintering Colony

Inland

Female

ABJ667

Loiton, \7V

12-Sep-Ol

06- Jan -02

El Rosario

Male

ABJS35

Lorton, V'A

22-Sep-Ol

26-Feb-02

El Rosario

Female

ABJ782

Lorton, \'A

13-Sep-Ol

26-Feh-02

El Rosario

Male

ABJ38S

Lorton, VA

04-Sep-()l

26- Feb-02

El Rosario

Female

ABJ41.5

Lorton, VA

05-Sep-01

20-Feh-02

Sierra Cliincua

Male

ABJ492

Lorton, \A

()fi-Sep-()l

27-Feh-02

Sierra Chinena

Female

ABJ675

Lorton, VA

12-8ep-01

27-Feh-02

Sierra Chinena

F’einale

AB|497

Lorton, VA

()6-Sep-0l

12- Mar-02

El Rosario

Female

ABJ484

Lorton, VA

06-Sep-01

24-Mar-03°

El Rosario

Female

ABJ682

Lorton, VA

12-Sep-Ol

03-Mar-04“

El Rosario

Male

ABj.538

Lorton, VA

07-Sep-()l

18-Mar-05‘’

El Rosario

Male

ABJ757

Lorton, VA

13-.Sep-01

lS-Mar-05°

El Rosario

Male

HCM412

VV'oodliridge, VA

03-Sep-Ofi

20-Feb-07

El Rosario

Coastal

Female

A 1 1.546

Cape Charles, VA

()2-Oct-01

18-.Vlar-05°

El Rosario

Female

HCM 160

Cape Charles, V^A

03-Oct-01

06-|an-07

El Rosario

“Time span greater than 1 o\'en\intering season hecause tag was found and held by local residents until collected by Monarch Watch officials

retuniing immediately began neetaring. Louise Zemaitis (pers. cfiinm.) has made similar obsemitions in Cape May.

Beall (1948) found that many monarchs perished while attempting to cross Lake Erie during the fall and he determined that they had a lower lipid content than monarchs that snnived the crossing. It therefore seems reasonable to conclude that migrants are forced to burn more lipid while using powered and flapping flight to contend wath the coastal vrinds and flights across water than the tenfold more energy-efficient soaring and gliding that is common in the less windy inland environment (Schmidt-Koenig 1985; Masters et al. 1988; Da\4s & Garland 2004; Brower et al. 2006).

Are the diminished neetar resources and low lipid levels due to human encroachment? As implied by onr having caught most of onr butterflies at flowers, monarchs frecpiently interrupt their fall migration to drink nectar. Sugar that is contained in nectar is converted to lipid that the butteidlies store and use to fuel their flight and other activities. In a recent study, Brower et al. (2006) found only moderate

amounts of lipids in migrating monarchs until they reach Texas, where tliey then accnmnlate large lipid stores. Lipid stores are critical to fuel the butterflies five month ovenvintering period in Mexico (Alonso et al. 1997).

We hyjrothesize that onr coastal monarchs were lighter than the inland monarchs because they did not have access to sufficient nectar sources and that this is due to a diminished flora caused by habitat deterioration along the Atlantic coastal migratory corridor. Wdiile the overall nectar abundance may always have been less along the coast than inland, as now discussed, this is doubtful.

The coastal habitats. The dynamic ecological interrelationships of coastal habitats are described in Frid & Evans (1995). They include long ribbons of barrier and sea islands that over geological time developed a series of veiy different habitats extending from the sea to inland (Christensen 1988). The habitats include the sandy beaches, coastal prairies, primaiy and secondaiy sand dunes and wetland swales behind the dimes (Silberhorn 1999). Further inland are saline and

Volume 62, Number 4

197

Table 4. Results of ANOVA wing length of migrating monarc 2004 year were not included in tl actions were initially included in when found not significant.

model explaining variation in li butterilies. The data for the le analysis. All two-way inter- the model but were removeil

Independent

df

MS F

P

Site

1

17 4.0

0.046

Year

3

46 10.5

<l).()01

Sex

1

15 3.5

0.064

Error

611

4

Total

616

freshwater estiiai'ies, lagoons, sounds and eoastal forests. Aceording to Delaconrt & Delaconrt (1981), tliis veiy dynamic ecosystem complex has persisted for tlie last 9000 years, about as long as the current monarch butterfly migration is thought to have existed (Brower 1995). Even though the various communities within this environmental can he complex and harsh (Barbour & Christensen 1993), they have specialized, productive and diverse floras (Barbour 1992; Tiner 1987, 1993; Packham & Willis 1997; Silherhorn 1999), These iuclude numerous annual and perennial plants that seiwe as nectar sources for the monarch butterfly migrating through the complex of habitats each fall.

According to Bird (1985), coastal erosion through rising sea level has impacted about 70% of the planet's sandy beach environments including those along the North American Atlantic coast. Rising sea level causes the beach, coastal prairie and dune habitats to erode, but, with slow rising conditions, the habitats reestablish further inland. They then undergo ecological succession anti the flora physically stabilizes the

Table 5, Re,snlts of ANOVA model explaining variation in wet ma.ss of migrating monarcl] butterflies. Tlie data for the 2004 year were not inclntled in the analysis. The interaetions of ■Site°Sex and Year°Sex were initially included in tlie model lint were removed when found not significant.

Independent df MS F p

Site

1

8280

1.9

0.164

Year

3

36516

8.6

<0.001

Sex

1

18595

4.4

0.037

WingLength

1

778160

182.5

<0.0()1

Sex'WingLengtl 1

1

14502

3.4

0.066

Site "’WingLength

1

12449

2.9

0.088

Site'Year

3

24216

5.7

0.001

Error

602

4263

Total

613

restored habitat. To what extent have humans diminished this environment?

Human encroachment. Hitman exploitation of the valuable economic resources offered by the dynamic coastal ecosystems and its severe impact on their natural features is documented in numerous studies (Turner et al. 1998; Doody 2002; Ray & McCormick-Ray 2003; Bnrronghs & Tebhins 2005; Feagin et al. 2005; Forman et al. 2005; Verhoeven et al. 2006; Martinez & PsuH 2007). The construction of buildings, dikes, parking lots, roads, etc. often stpieezes the land against the ocean and blocks the natural inland sand movement. Sea currents then either wash the sandy beaches, the prairies and the dimes away, or reduce them to mere remnants with e.xtensively diminished floras. It is estimated that 350,000 structures in the United States are located within 500 feet of tlie shorelines and nearly half of all coastal wetlands have been destroyed since pre-Columbian times (Beatley ct al. 2002). Dredging and ditching in the first half of the 20th centniy also deteriorated much coastal habitat (Humphrey and Rockefeller 1968), Although passage of the 1972 Wetlands Act helped mitigate tlie losses, Beatley et al. (2002, p. 283) tell ns: "Alarm bells are ringing eveiywhere as our coastal eiiviroiiment endures unabated development pressures and environmental degradation".

Another negative anthropogenic impact is the spraying of herbicides, including gly^ihosate ("Roundup", Monsanto, Inc., see Anon. 2005) and iniazapyr ("Habitat", BASF Inc., see Anon. 2007b), to control marsh reed grass, Phragmite.s australis (Cav.) Trill, ex Steud. (Poaceae). These biocides, either directlv or through inadvertent wdiid drift wlien applied by helicopters, can kill the nectar sources adjacent to the marshes. For example, spraying herbiciiles was a major issue in Cape May in 2005 (Fichter 2005) and in the Chincoteague National Wildlife Refuge iii 2006. According to Denise Gibbs (pers. comm.), helicopter spraying on Chincoteague is forbidden if the wind exceeds 5 mph. However, on 2 October 2006 — a peak monarch butterfly migration day — the spraying was continued with a 15 mph wind, drifting "Habitat" for at least a half a mile across a main Soliclago sempervirens nectaring area. Yet other impacts are e.xemplified by helicopter spraying of malathion (see Anon. 2006) and by truck misting with the pyrethroid derivative resmethrin, ("Scourge", Aventis Environniental Science, see Anon. 2007c) for mosquito control by the Cape May County Mosquito Commission. A related synthetic pyrethroid ("Perniethrin") has been found to kill monarchs in lioth larval and adult stages and has long term effects on the butterflies (Oberhauser ct al. 2006).

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The extent to which these various physical and chemical impacts have diminished the quantity and quality of the nectar sources in the coastal enwronment has not been quantified, but the losses have almost certainly affected the lipid and hydration dynamics of fall migrant monarch butterflies, as well as the nectar re(|iiirements of other animals living in and using tins migratoiy corridor (Nabhan 2004; Brower & Pvle 2004).

Inland habitats. In contrast to the natural and anthropogenic hazards to monarchs flying along the coast, flight over the far more extensive inland routes wdth diverse and varied nectar resources may not be as stressful. Inland environments are also subject to less intense wind and, until recently, I'oadsides and agricultural fields provided extensive areas with wildflowers. Unfortunately, the ever-increasing use of herbicides on roadsides, and, in conjunction with the repeated spraying of corn and soybean crops that are genetically engineered to be resistant to the herbicides, are eliminating huge areas of floral resources (Brower et al. 2006).

Alternative hypotheses and future research. An

alternative hvpothesis to account for the smaller and lighter coastal monarchs is that fewer of their laiwae had the opportunity to feed on Asclepias sifriaca L. (Asciepiadaceae), the major food plant (Malcolm et al. 19S9) of the monarch's eastern population and is known to be nutritionally superior to Asclepias tuberosa L. (Erickson 1973). The latter milkAveed is widely distributed along the Atlantic coast (Woodson 1954), and it is possible that more of the coastal migrants had fed on it and ended up as smaller indiwduals. Thin layer chromatography analyses (Malcolm et al. 1989) could determine if tlie food plants eaten by the lan ae differed among the larger and smaller inclMdual butterflies. However, this explanation seems unlikely because, as implied above, the majority of coastal monarchs probably fed on A. sifriaca plants growing inland before being wind-drifted to the coast.

Another possibility is that the smaller and lighter monarchs were less able than the larger and heavier ones to resist winds that blew them towards the coast. This is consistent with Beall's (1948) finding that the monarchs that drowned crossing Lake Erie were both smaller and lighter than ones he collected in roosts both north and south of the lake collections. Another possibility is that the monarchs with lower mass were more fuel and/or water stressed and therefore accumulated on the coast to nectar, while the heavier ones kept migrating south. It is important to remember that our samples were gathered in a veiy limited latitudinal transect. Much light could be shed on the questions by analyzing collections along the coast as the

migration progresses from Maine to Elorida.

To test onr habitat deterioration hypothesis, comparative measurements of the amount of nectar imbibed by monarchs (methods in Brower et al. in prep.) collected at inland and the coastal sites could be made. Currently, there are hundreds of citizen- scientists (Monarch Watch 2006; Prysby & Oberhauser 2004) who study, capture, tag and release monarchs each year. Direct measurements of wdng length and wet mass, as done in this study without killing the individual monarchs, would help build long term comparative data sets. However, more accurate measurements of both lipid and water contents of the inland and coastal monarchs are needed. Wet mass is the sum of the w^ater, lipid and the lean body mass. Consequently, the coi'relation between wet mass of the whole butterfly and the contained lipid mass is weak and confounds the masses of water and lipid. In order to measure both accurately, the moiiarchs must be killed by freezing, w'eighed, dehydrated, weighed again, and then their lipids extracted and w^eighed (Brower et al. in prep.). Citizen-scientists conld collect and freeze monarch samples and have professionals cany out the lipid and water determinations in a w^ell-coordinated project.

Acknowledgements

We thank the following for field assistance in Virginia: Sharna Tolfree, Randy Emmitt, David Haynes, and Elizabeth Townsend, all supported by the Coastal Virginia Wildlife Obser- \ atorv. Logistic support was also provided to Brindza by the Oc- coquan Bay National Wildlife Refuge, Eastern Shore of Virginia National Wildlife Refuge, Mason Neck State Park, Kiptopeke State Park, and the Chesapeake Bay Bridge-Tunnel. We are grateful to Linda Fink, Richard Walton, Louise Zeniaitis and two reviewers for critical comments on the manuscript, to Denise Gibbs for sharing information on the migration through Chincoteague, VA., and to Peter Raven for identifying scientists familiar with the Atlantic coastal flora, including Michael Bar- bour, James Morris, Gerry Moore, George Yatskiev)'ch; and to Janet Steven. We appreciate the enormous efforts of Orley Tay- lor in coordinating the Monarch Watch tagging program, for purchase of recovered tags in Mexico and for disseminating re- capture data. Robert Dudley, though skeptical of our wdnd loss hypothesis, provided v'aluable commentaiy and insights. Finan- cial support was provided over the years by The Wildlife Con- seiwation Society, Paul and Kathy Reinhold, The October Hill Foundation, and by National Science Foundation grant DEB- 0415340 to Sweet Briar College with Lincoln Brower and Linda Fink as principal iiwestigators. AKD was supported by the D.B. Warnell School of Forestry and Natural Resources at the Uni- versity of Georgia during the writing of this manuscript.

Literature Cited

Alexander, D. E. 2002. Nature's flyers. The Johns Hopkins Univer- siy Press, Baltimore, Maryland.

Alonso-Mejia, a., E. Rendon-Salinas, E. Montesinos-Patino, & L. P. Brower. 1997. Use of lipid reserv'es by monarch buttenflies overwintering in Mexico: implications for conservation. Ecologi- cal Applications 7: 934-947.

Anon. 200.5. Monsanto imagine: Backgrounder history of Monsanto's glyphosate her'bicides, June 2005, http://vvAvw.nronsanto.eorn/

Volume 62, Number 4

199

p(H/prodiicts/ronndup_l);ick_histon'.pdf. Accessed 19 November 2007.

. 2006. Cape Vlay CoimW Mosquito Control Commission.

http://e.\ecdeanagricn It lire, rntgers.edu/pliotos/al hum. asp? mos(juitocontrol2006. Accessed 19 November 2007.

. 2007a. Plants database. In USDA Natural Hesources Conser-

\ation Senice littp://plants. usda.gov Accessed 11 September 2007.

. 2007b. Imazapvr. W'eed Control Methods Handbook, The Na- ture Consenaucy. http://tnc\veeds,ucda\is.edu/products/ handbook/1 7.Imazapvr.pdf. Accessed 19 November 2007.

. 2007c. Scourge ;uid mosquito control In New York Depiulineut ol

Ilealtli Intonnation Sheet "Scoiu'ge and mosquito couOol". http://v'ww.liealth. state. US'. ns/nvsdoli/westnile/education/27.39.htm.

Accessed 19 November 2007.

A'nvoon, W. \V. 1940. The physiographic provinces of North America. Ginn and Company, Boston, Massachusetts.

B.vrbour, M. G. 1992. Life at the leading edge: the beacli plant smi- dronie. Pp. 291-307 . In U. Seeliger (ed.k Coastal plant commu- nities of Latin America. Academic Press. San Diego.

, & N, L. Christensen. 1993. Vegetation. Pp. 97-13! . In N. R.

Morin (ed.). Flora of North America. Oxford University Press, New York.

Beall, G. 1948. The fat content of a butterlly, Duninis plexippus, as affected bv migration. Ecologv' 29: 80-94.

Beatlev, T, D. (. Brower, & A. K. Schwab. 2002. An introduction to coastal zone management, 2nd edition. Island Press, Washington, D.C.

Bird, E. C. F. 1985. Coastal changes: a global review. John YYiley and Sons. Chichester, IIK.

Borland, J., C. C. Johnson, T. W. Crumpton III, ,\L Thomas, S. Al- TIZER, & K. Oberhausrr. 2004. Characteristics of fall migraton' monarch butterflies, Danaus plcxip}>ii.s, in Minnesota and Texas. Pp. 97-104 . In K. Oberhanser & M. Solenskv (eds.). The monarch butterfly, biology and conseiwation. Cornell University Press, Ithaca, NY.

Brower, L. P. 1995. Understanding and misunderstanding the migra- tion of the monarch butteidlv (Nvinphalidae) in North America: 1857-1995, Journal of the Lepidopterists' Society 49: 304-385.

. K. B. Kust, J. Miller, C. P’ernandez del Key, & K. Pape.

2004. Catastrophic winter storm mortality of monarch butterflies in Mexico during January 2002. Pp. I5i-166 . In K. S. Ober- hauser & M. J. Solenskv (eds.). The monarch butterfly, biologx' and conseiA'ation. Cornell University Press, Ithaca.

. L. S. Fink, & P. Walford. 2006. Fueling the fall migration of

the monarch butterfly. Integrative and Comparative Biologv' 46: 1123-1142.

& R. M. Pyle. 2004. The interchange of inigratoiw monarchs

betw'een Mexico and the western United States, and the impor- tance of floral corridors to the fall and spring migrations. Pp. 167-178 . In G. P. Nabhan (ed.), Consening migraton- pollina- tors and nectar corridors in w-esteni Nortli America. The Univer- sity of Arizona Press and The Arizona-Sonora Desert Museum, Tuc.son, AZ.

Brown, J. J., & G. M. Chippendale. 1974. Migration of the monarch Imtterfly, Danaus plexi]>pus: energ)' sources. Journal of Insect Physiology 20: 1 1 17-1130.

Burroughs, S. M., & S. E. Tebbens. 2005. Dune retreat and sliore- line change on the Outer Banks of North Carolina. Abstract, De- cember, American Geophysical Union, San Francisco. http://wavw.agu.org/cgi-bin/SFgate/SP’gate

Christensen, N. L. 1988. Vegetation ol tlie southeastern coastal plain. Pp. 317-363 . In M. G. Barbour & W. D. Billings (eds.). North American Terrestrial Vegetation. Cambridge University' Press, Cambridge, England.

D.wis, A.K., & M. S. Garland. 2002. An evaluation ol three methods ot counting migrating monarch Imtterllies in vamngw-ind condi- tions. Southeastem Naturalist 1: 55-68.

, & . 2004. Stopover ecology of monarchs iu coastal Vir- ginia: using ornithological methods to study monarch migration.

Pp. 89-96 . In K. (.llierhauser & M. Solenskv (eds.), Tlie monarch butterflv. biology- and consen-ation. Cornell Universitv Press, Ithaca, NY'.

Delacourt, P. a. & 11. R. Delacourt. 1981. Vegetation maps for eastern North America: 40,000 vr B P. to the present. Pp. 123-165 . In R. C. Romans (ed.). Geobotany II. Plenum Press, New York.

DOCK.X, C., L. P. Brower, L. I. Wassenaar & K. A. Hobson. 2004. Do Nortli American monarch biitterllies trav-el to Cuba? Stable isotope and chemical tracer techniques. Ecological Applications 14:1006-1114.

Doody, j. P. 2002. Coastal consen-ation and management: an ecologi- cal perspective, Kluw-er Academic Publishers, Boston, Massachu- setts.

Dlidley, R. 2000. The biomechanics of insect flight; form, function, evolution. Princeton University- Press, Princeton, Neyv Jersey.

Dudley, R., & R. B. Syrgley. 2008. Airspeed adjustment and lipid re- seives in migraton- Neotropical butterflies (Lepidoptera: Pieridae and Ny-mphalidae). Functional Ecology 22: 264-270.

Erickson, J. M. 1973. The utilization of various Asclepias species bv lanae of the monarch butterfly-, Danaus j)lexippus. Psyche 80; 230-244.

Feagin, R. ,A., D. j. Sherman. & W E. Grant. 2005. Coastal erosion, global sea-level rise, and the loss of sand dune plant habitats. Frontiers in Ecology- and the Emironment 3: 359-364.

Fighter, J. 2005. Herbicide spraying continues, so do worries, p. 9 . In Cape May County- Herald, 5 October 2005, Cape Vlav, New Jersey.

Forman, S. L., Z. Sagintayev, S. .M. Smith, M. I, Sultan, & R. Beck- ERR. 2005. The relation bety\-een 20th centun- dune migration and yy-etland formation at Cape Cod National Seashore. M.A. Ab- stract, December, American Geophysical Lhiion, San Francisco. htqi://yyAy-yv.agu.org/meetings/fm05/im05-session,s/fm05_H43D.html Accessed 4 December 2007.

Frid, C. L. j., & P. R. EVAN.S. 1995. Coastal habitats. Pp. 59-83 . In W. J. Sutherland & D. A. Hill (eds.). Managing habitats for conser- vation. Cambridge University' Press, Cambridge,

Garland, M. S., & A. K. Davis. 2002. An examination of monarch butterily {Danaus plexippus) autumn migration in coastal Y’ir- ginia. American Midland Naturalist 147: 170-174.

Gibbs, D. 2007. .Assateague Island, Y'irginia at Chincoteague National Wildlife Refuge. Monarch Watch, LavyTence, Kansas. 2 October 2007, DPLEX-L digest 4012. Accessed 3 October 2007.

, R. Walton, L. Brower, & A. K. D.wis, 2006. Monarch but- terflv (Lepidoptera, Ny-mphalidae) migration monitoring at Chin- coteague, Y'A and Cape .Vlav, NJ: a comparison of long-term trends. Journal ol the Kansas Entomological Society- 79: 156-164. '

Giro, D.L., & J. A. McCurdy. 1993. Lipid accumulation by- monarch Imtterllies {Danaus plexippus L.), Canadian journal of Zoology- 71: 76-82.

IIoyvARD, E. 2007. (Fall migration roost formation, animated as mon- archs migrate south). On: the Jonrney North yvebsite: li 1 1 p : / / yy- yy- w . 1 e a r n e r . o r g / j n o r t h / 1 m / m o n a r c h / FalkVligrationTiming.html, accessed 23 September 2007.

Humphrey, II. N., & L. S. Rockefeller. 1968. From sea to shining sea: a report on the American environment — our natural her- itage. President Ly-ndon B. Johnson's Council on Recreation and Natural Beauty, W'ashington, D.C.

ISHii, M., L. P. Brower, and T. Van Hook. 1992. Autumnal move- ments of monarch butterflies along the Gulf Coast in Florida. Page 178 . In Transactions of the XIX International Congress ol Entomology-, Beijing, China.

Knight, A. L. 1998. A population study of monarch butterllies in north-central and south Florida. M.S. Thesis, yfii +125 pp.

Lobstein, M. B. 1990. Summer and fall yy-ildlloyvers of Northern Y'irginia: A checklist. Prince W'illiam YVildlloyy-er Society, Manassas, Y'A.

-Malcolm, S. B., B. J, Cockrell, & L. P. Brower. 1989. Cardenolide fingeqrrint of monarch butterflies reared ou common milkweed, Asclepias sipiaca L. journal of Chemical Ecology 15: 819-853.

200

JOUKNAL OF THE LePIDOPTERISTS’ SoCIETi'

Martinez, M. L., & N. P. Psuty (eds.). 2007. Coastal dunes: ecology and consei'vation (ecological studies). Springer- Verlag, Berlin.

Masters, A. R., S. B. Malcolm, & L. P. Brower. 1988. Monarch but- terfly {Danaus plexippus) thermoregulatory behavior and adapta- tions for oveiAvintering in Me.rico. Ecology 69: 458-467.

McNeil, D. G., Jr, 2006. Fly away home. The monarch migration mysteiy. Pages D1 and D.3 . In .3 October 2006 edition. New York Times, New York.

Monarch Watch. 2006, Tag recovery database. http:// WWW, monarch watch.org/ tagmig/recoveries.htm. Accessed 1 October 2007.

Nabhan, G. P. 2004. Stress on pollinators during migration. Pp. 3-22. In G. P. Nabhan (ed.), Conserxing migratory pollinators and nec- tar corridors in western North America. The University of Ari- zona Press and The Arizona-Sonora Desert Museum, Tucson AZ.

Newcomb, L, 1977. Newcomb's wildflower guide. Little, Brown and Company, Boston.

Oberhauser, K. S„ S. J. Brinda, S. Weaver, R. D. Moon, S. A, Man- weiler, & N. Read. 2006. Growth and survival of monarch but- terflies (Lepidoptera: Danaidae) after exposure to permethrin barrier treatments. Emaronmental Entomology 35: 1626-16.34,

Packham, J. R., & A. J. Willis. 1997. Ecology of dunes, salt marsh and shingle. Chapman Hall, London.

Peterson, R. T. & M. McKenny. 1968. A field guide to vrildflowers of northeastern and north-central North America. Houghton Mif- flan Company, Boston and New York.

Prysby, M., & K. S. Oberhauser. 2004. Temporal and geographic variation in monarch densities: citizen scientists document

monarch population patterns. Pp. 9-20 . In K. Oberhauser & M. Solensky (eds.). The monarch butteidly: biology and conservation. Cornell Universit)' Press, Ithaca, NY.

Raisz, E. j. 1957. Map of the landforms of the United States: to ac- company Atwood's Physiographic provinces of North America. 6th revised edition. Published by the author, Cambridge, Massa- chusetts,

Ray, C. G., & J. McCormick-Ray, 2003, Coastal -marine conservation: science and policy. Blackwell Publishing Limited,

Richardson, W. J. 1990. Wind and orientation of migrating birds: a reriew. Cellular and Molecular Life Sciences 46: 416-425.

Rogg, K. a., O. R. Taylor, & D. L. Gibo. 1999. Mark and recapture during the monarch migration: a premilinary analysis. Pp. 133-138 . In ]. Hoth, L. Merino, K. Oberhauser, I. Pisanty, S. Price, & T. Wilkinson (eds.), in: Paper presentations: 1997 North American Conference on the monarch butteiHy (Morelia, Mex- ico.). The Commission for Environmental Cooperation, Mon- treal, Canada.

Schmidt-Koenig, K. 1985. Migration strategies of monarch butter- flies. Pp. 786-798 , In M. A. Rankin (ed.). Migration: mechan- isms and adaptive significance. Univ. Texas Contrib. Marine Sci., Austin, TX27 (Supplement).

. 1993. Orientation of autumn migration in the monarch butter- fly, Pp. 275-283 . In S. B, Malcolm & M, P. Zalucld (eds.). Biol- ogy and conservation of the monarch butterfly. Natural History

Museum of Los Angeles County, Los Angeles, California.

Silberhorn, G. M. 1999. Common plants of the mid-Atlantic coast: a field guide, rerised edition. The John Hopkins University Press.

Smith, B. 2007. View from the field: monarch update 10/16/07. bird- capemay.org/sightings/ Accessed 17 October 2007.

Statistica. 2003. Statistica version 6.1, Statsoft, Inc, Tulsa, OK.

Syrgley, R. B. 2004. Wind drift compensation in migrating dragon- flies Pantala (Odonata: Libellulidae). Journal of Insect Behavior 16: 217-232,

Tiner, R. W. 1987. A field guide to coastal wetland plants of the northeastern United States. University of Massachusetts Press, Amherst, Massachusetts.

. 1993. A field guide to coastal wetland plants of the southeast- ern United States. University of Massachusetts Press, Amherst, Massachusetts,

Turner, R. K., I. Lorenzoni, N. Beaumont, I. J. Bateman, I. H. Langford, & A. L. McDonald. 1998. Coastal management for sustainable development: analysing environmental and socio-eco- nomic changes on the UK coast. The Geographical Journal 164: 269-281.

Urquhart, F.A. 1987. The monarch butterfly: international traveller. University of Toronto Press, Toronto.

& N. R. Urquhart, 1979a. Aberrant autumnal migration of the

eastern population of the monarch butterfly, Danaus p. plexippus (Lepidoptera: Danaidae) as it relates to the occurrence of strong westerly winds. Canadian Entomologist 111: 1281-1286.

& . 1979b. Breeding areas and overnight roosting loca- tions in the northern range of the monarch butterfly (Danaus plexippus plexippus) with a summary of associated migratory routes. The Canadian Field Naturalist 93: 41-47.

Verhoeven, j. T. a., B. Beltman, R. Bobbink & D. F. Whigham. 2006. Wetlands and natural resource management (ecological studies). Springer.

Walton, D. 1999. 1998 monarch migration project: seasonal sum- mary, Peregrine Observer (Cape May Bird Observatory) 21: 6-7.

Walton, R. K. & L. P, Brower. 1996. Monitoring the fall migration of the monarch butterfly Danaus plexippus L. (Nymphalidae: Danainae) in eastern North America: 1991-1994. Journal of the Lepidopterists' Society .50: 1-20.

& . 1999. What we know that ain't so the 1998 fall At- lantic Coast monarch migration. American ButteiHies 7: 18-25.

. , & A. K. Davts. 2005. Long-term monitoring and fall mi- gration patterns of the monarch butteilly (Nymphalidae: Danainae) in Cape May, NJ. Annals of the Entomological Society of America 98: 682-689.

Woodson, R. E., Jr. 1954. The North American species ol Asclepias L. Annals of the Missouri Botanical Garden 41: 1-211.

Zemaitis, L, 2005. Monarch monitoring project: 2004 season sum- mary. Peregrine Observer (Cape May Bird Observatory) 27: 18-19.

Received for publication 31 January 2008; revised and accepted 9

September 2008.

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A REVIEW OF GEOGRAPHIC VARIATION AND POSSIBLE EVOLUTIONARY RELATIONSHIPS IN THE COLIAS SCUDDERll-GIGANTEA COMPLEX OF NORTH AMERICA (PIERIDAE)

Paul C. Hammond

Department of Zoology, Oregon State University, Con alli.s, Oregon 97331

AND

David V McCorkle

Department of Biology', Western Oregon University, Moimioutli, Oregon 97361: email: inccorkd@wou.edn

ABSTKACT. The geographic variatioTi in the Colias sciuldcrii-gigtmica complex oi Nortli America is rexiewed. Transitional populations sug- gest that C. oi^autca should be taxonomically treated yUthin a broader poivtyjric concept ol C. scuddchi. Two of tliese transitional populations are described as new subspecies: C. a. oracemma in the Big Horn Mountains of Wyoming and C. s. ktihicri in tlie mountains of western Mon- tana. In addition, C. s. nortcpacifica, new subspecies, is described from a remote region of southwestern British Columliia. Possible evolu- tionaiy relationships are examined yUth regard to tlie biogeography and paleoliistorical climatic fluctuations and glaciations of the Pliocene-Pleis- tocene periods over the past seven million years. A phylogenetic hypothesis for the chn/sothcinc species group of Colias is presented tliat postulates reticulate hy'brid fusion or introgression has play'ed an important role in the evolution of this group ol Colias.

Aclditionul key words: Biogeographv, phy logeny, glaciations. Pliocene, Pleistocene.

The genus Colias (Pieridtie: Coliatliuae) is a large and complex group of bntterHies that is widely distributed throughout most ol tlie world. Verlmlst (2()()0) provided a monographic treatment of the genus, and recognized up to 85 species-level taxa. I lowever, many of these taxa may be geographic subspecies or semispecies of complex poKtvpic species or superspecies (Hammond & VIcCorlde 2003). The genus is highly cousen ative in morphology with minimal geuitalic dillereuces among most ol the species, with the exception ol tlie subgenns Zcrene (Verlmlst 2000). Eleven ma]or species groups may be distinguished witliin the genus on the basis of wing color pattern characters, including tlie snbgenns Zcrene. The latter group is often elevated to full generic status on the basis ol moiphological divergence.

Over the past twentv years, we have conducted extensive studies of species complexes closely related to C, occiclentalis Scudder within the chnjsotheine group of species. The present paper seiwes as an introduction to this group, and provides a detailed review ol the C. scudderii-gigantea complex. Additional papers are planned that wall review the C. jtelidne-palaeno complex and the C. occidenfalis-alcxandra complex. These complexes are of considerable interest from an evolntionaiw perspective. E\’olntionar\' tlieoiy predicts that intermediate or transitional linkages should exist in modern day species complexes resulting from incipient speciation processes. As a consequence, the tiLxonomic delineation ol species boundaries is often dilficnlt lor such intermediates. Such complexes may provide considerable evidence regarding the actual mechanical

pi'ocesses of cladogenesis and speciation as they luwe taken place in the past, and may be taking place today.

As we define the clin/sotheme species group, it consists of 11-15 .species, depending upon interpretations ol species boundaries. This group is confined to North America, with the e.xception of two species that are wadespread in Eurasia. It is most similar and probably most closely related to the crocea species group in Eurasia and Alrica, but dillers in the absence of an androconial scale patch on the costal margin ol the male dorsal hindwing. Other wang pattern characters that sewe to distinguish most members oi the chn/sofhenie group trom the crocea group include (1) a lighter orange to yellow' dorsal ground color, (2) reduced size ol discal spots on lore and hindwangs, and (.3) a reduction or absence ol heavy black melanic scaling on the dorsal hindwang of females. How'ever, the Eurasian C. chnjsotheme Esper tends to be intermediate in these latter characters betw'een the North American species ol the chri/.sothemc group and C. crocea Fonrcroy.

Within the chri/sotheinc group, we recognize two subgroups based upon biology and some w'ing color pattern differences. The chri/sofheme subgroup

consists ol the Eurasian C. chri/sotlieinc and the North American species C. enn/thetne Boisdnval and C. phdodice Godart. Togetlier w'ith C. crocea, tliese .species are characterized on the ventral hindwing by having a double-ringed discal spot and black snbmarginal spots. Females always have hilly

tleveloped black borders on the dorsal wangs, and a

202

Journal of the Lepidopterists’ Societt'

simple yellow-orange or white (alba) color dimorphism. All four species are highly vagile or even migratoiy. Their lamie feed on weedy legumes (Fabaceae) such as Vida, Trifolium, and Medicago species that colonize disturbed and temporaiy habitats.

In shaqr contrast, the occidentaJis subgroup is usually characterized by having a single-ringed discal spot and reduced or absent black snhmarginal spots on the ventral hindwing. The black border of females is often reduced or completely absent. In addition, females also show an intermediate yellow-white or cream (semi-alba) color moqrh. These species are often very sedentaiy, and live in veiw local colonies in association with more stable habitats that support long-lived, perennial lan al foodplants. The subgroup is comprisetl of three closely related species complexes that show numerous intermediate linkages. Colins occidcntalis Scndder and C. alexaudra Edwards form one complex that feeds on legumes, with C. occidentalis being possibly the primitive, ancestral species oi the subgroup because of its close similarities with C. pliilodice and C. eurijdunnc. A more specialized, derived complex ol species leed on Vacciuiinn shrubs (Ericaceae) growing in montane, boreal, and high Arctic habitats. These include the North American species C. pclid)ie Boisdnval, C. interior Scndder, C. behrii Edwards, C. chippetva Edwards, and the Eurasian species C. palaeno Einnaens. A third group that appears to be closely related to both C. occidentalis and C. pelidnc is the C. sctiddcrii-gigantea complex, leeding primarily on dwarf willows (Salix spp. - Salicaceae) growing in montane, boreal, or Arctic regions of North America. This species complex is the subject of the present paper.

Eerris (1987) has prepared the most recent monograph of the C. scudderii-gigantea complex. He recognized two separate species, C. scudderii Reakirt isolated in the southern Rockw Mountains, and C. gigantea Strecker distributed through the central and northern Rocky Mountains and across Canada and Alaska. However, other authors such as Scott (1986) have treated C. gigantea as a geographic subspecies of C. scudderii. In recent years, much additional information has been acquired from important geographic localities through the central Rocky Mountains. Four different intermediate populations show transitions from the txqrical Colorado C. scudderii to more northern populations of the gigantea type as discussed below. These are distributed in northeastern Utah, Wyoming, aird southwestern Montana. Thus, we follow the tiLxonomic treatment of Scott (1986) in combining ttuxa of the gigantea tyjie within a broader polyt)qric concept of C. scudderii.

Materials and Methods

For this study, we e.xamined about lOOO specimens of the C. scudderii complex from throughout the distribution of this species, but particularly from the Rocly’ Alountain region. In addition, we also examined about 900 specimens of C. occidentalis from across central Oregon to examine the relationship of this species to the C. scudderii complex.

Because of strong sexual dimoiphism in this complex, males and females were studied separately. We measured forewing length from the wing base to the apex. We also quantified three wing color pattern characters in the male and two cluiracters in the female. These characters all show continuous variation, and are probably controlled by polygenic complexes of multiple loci and alleles. However, for the pnipose of this work, we wanted to simplify the analysis by reducing the variation classification to only a few classes. The characters and their classification are defined as follows.

1. Male ventral hindwing ground color olive-green, yellow-green, yellow, or orange. Since these colors present a situation of contimujus variation and are probably highly polygenic, orange was classified as any tint of orange, ranging from very dark orange to pale yellow-orange. Likewise, olive-green was classified as darkei' shades without any yellow tinge, while yellow- green was classified as a paler green shade with a distinct tinge of yellow.

2. Male discal spot on ventral hindwing large, medium, or small. Spot size also shows a continuous range of variation, and was the most difficult to classify in an objective manner. A large spot was defined as covering one half or more of the discal cell wdth at the distal end of the cell, while a small spot covered only one third or less of discal cell width. A medium spot was subjectively treated as intermediate between these extremes. We also considered a subcategory of large spot called a giant spot that covers nearly Rvo thirds of the discal cell width.

3. Male discal spot on ventral hindwing with or wTthout a satellite spot.

4. Female dorsal ground color yellow, cream (semi- alba), white (alba), or orange. Again, orange was classified as any shade of orange including an orange flush on a yellow background.

5. Female black wing border on dorsal forewing heavy (both inner and outer parts of border present), reduced (usually only a thin portion of inner border present), or absent (only slight black traces of border present or none).

Tables I and 2 show the frequencies of polymoi-phic variants within these five characters in various

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203

Table 1. Frequencies of phenoRqric variation in males of Colias si hindwing at various geographic localities.

ciidderii for ground color, discal spot size, and

satellite .spots

on the ventral

Localit)'

olive-green yell

ow-greeii

yellow

orange

large

medium

small

sat.

no sat.

1

0.79

0.21

0.00

0.00

0.25

0.30

0.45

0.27

0.73

2

1.00

0.00

0.00

0.00

0.33

0.33

0.33

0.50

0.50

3

0.26

0.74

0,00

0.00

0.55

0.25

0.20

0.84

0.16

4

0.25

0.25

0,50

0.00

0.65

0.27

(.).08

0.75

0.25

5

0.00

0.00

0.69

0.31

0.54

0.23

0.23

0.81

0.19

6

0.00

0.01

0.67

0.32

0.46

0.26

0.28

0.73

0.27

7

0.04

0.24

0.63

0.09

0.50

0.28

0.22

0.82

0.18

8

0.00

0.00

0.60

0.40

0.43

0.37

0.20

0.83

0.17

9

0.00

0.00

0.28

0.72

0.38

0.28

0.34

0.66

0.34

10

0.00

0.00

0.58

0.42

0.37

0.32

0.31

0.89

0.11

11

0.00

0.00

0.50

0..50

0.25

0.33

0.42

0.92

0.08

12

0.05

0.05

0.40

0.50

0.35

0.45

0.20

0.80

0.20

1. Colorado, Rocky Mts. n = 108 (C, s. scudderii)

2. Utah, Uinta Mts. n = 6 (C. .sn^Wcni llinta population)

3. Wyoming, Big Horn Mts. n = 73 (C. s. gracemma)

4. Wyoming, Wind River Mts. n = 55 (C. s. Iiarroiveri)

5. Wyoming, Absaroka Mts. n = 26 {C. .s. kohlcii)

6. Montana, Centennial Mts. n = 95 (C. s. kolderi)

7. Montana, Pioneer Mts, n = 147 (C. s. kohlcii)

8. Montana, Flint Creek Mts. n = 35 (C. .s. koJderi)

9. Alberta and Britisli Columbia n = 29 (C. s. mai/i)

10. Manitoba, Riding Vlts. n = 19 (C. .s. nun/i)

11. Manitoba, Hudson Bay at Churchill u = 12 [C. s. gigantea)

12. Yukon and Alaska n = 20 (C. s. gigantea)

populations of the C. scudderii complex at strategic locations across the North American landscape. We attempted to assemble a minimum sample of 10 specimens for each population to show at least the major variations within these populations, althougli 15-20 specimens provides better insight into frequencies. The larger samples of 50 or more were useful for detecting rare variants in populations. It should be noted that these are composite samples comprised of individuals from many localities, and do not represent single or local colonies.

Results and Discussion

CoUas occidentalis and possible evolutionai'y relationships. Relationships among the various Colias species in western North America have been veiy confused in the past. This is due to the existence of numerous intermediate or transitional populations, not only within species complexes, but also betw^een complexes. Hybridization also appears to be an important evolutionaiy process in these butterflies. As a consequence, applying the taxonomic definition of

species has been veiy difficult, often arbitrary, and artificial. We are using the biological species concept based upon reproductive isolation in syrnpatiy, but even this concept is often inadequate for the taxonomic delineation of species boundaries. Nevertheless, the various intermediate or transitional populations that exist in the modern day provide much evfidence regarding the past evolutionaiy histoiy of the butterflies, and are the basis for the following evolutionaiy theories.

Ferris (1993) conducted a cladistic analysis of the group, and recognized five species feeding on legumes within the occidentalis subgroup. The ty|)ical lorm of C. occidentalis along the West Coast is yellow with no UV- refiectance. It is extremely similar to C. phiJodice eriplujle Edwards in most characteristics, particularly those C. occidentalis populations in southwest Oregon and northwest California. The primaiy differences between the two species are that C. occidentalis has a single-ringed discal spot and heavier black melanic scaling on the ventral hindwing. By contrast, populations in the central and northern Rockv Mountains and across central Canada are more

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Table 2. Frequencies of plienotvpic variation in ieiniJes of Colias various geographic localities.

ior dorsal ground color and development of the black vring border at

Locality'

white

cream

yellow

orange

heavy

reduced

absent

1

0.50

0.19

0.31

0.00

0.03

0.19

0.78

2

0.60

0.20

0.20

0.00

0.00

0.00

1.00

3

0.30

0.38

0.30

0.02

0.18

0.32

0.50

4

0.05

0.10

0.76

0.09

0.09

0.57

0.34

5

0.08

0.33

0.58

0.00

0.42

0.17

0.41

6

0.22

0.17

0.61

0.00

0.39

0.39

0.22

7

0.19

0.10

0.70

0.01

0.09

0.20

0.71

8

0.00

0.00

0.88

0.12

0.18

0.41

0.41

9

0.00

0.14

0.86

0.00

0.14

0.29

0.57

10

0.67

0.33

0.00

0.00

0.00

0.50

0.50

11

0.70

0.30

0.00

0.00

0.30

0.40

0.30

1.

Colorado, Rockv Mts.

n = 32

(C. s. sciitldciii)

2. Utah, Uinta Mts. n = 5 (C. .snu'Werii Uinta population)

3. Myoining, Big Mom Mts. n = 40 (C. s. graccmma)

4. WVoniing, ^\’ind River Mts. n = 21 (C. s. harroiceri)

5. W voining, Absaroka Mts. n = 12 (C. s. kohleii)

6. Montana, Centennial Mts. n = 23 (C. s. kolileri)

7. Montana, Pioneer Mts. n = 87 (C. s. kohleri)

8. Alberta and British Columbia n = 17 (C. s. mayi)

9. Manitoba, Riding Mts. n = 7 (C. s. mayi)

10. -Manitoba, Hudson Bav at Churchill n = 6 {C. s. gigontea)

11. Yukon and .Alaska n = 10 (C. s. gigantea)

divergent wdth orange dorsal color and UV-reflectance on both fore and hindwdngs of males. Ferris (1993) recognized these populations as three ta.\onoinic species, C. christina Edwards, C. pseudochristina Ferris, and C. krauthii Klots. The fifth legume feeder is C. alexandra, which is mostly yellow with a U\^- reflecting patch on the dorsal hindwing. Finally, Ferris (1987) also reported C. gigcintea from central Oregon.

Whrren (2005) has followed Ferris (1993) in treating C. christina as distinct from C. occidcntalis. However, as discussed by Hammond & McCorkle (2003), a long clinal gradient between yellow occidcntalis forms and orange christina forms exists across the entire Intermountain region between the Cascades and Rockw Monntains. We examined long series of specimens from many localities. The Cascade populations are nearly monomoii^hic yellow, but one orange specimen was found in Jefferson Conntv, Oregon at the closest geographic point between the Cascades and the Ochoco Mountains to the east. This gives a ratio of about 99% yellow and 1% orange tor the Jefferson County population. Eastward, we found the yellow-orange ratio to be about 90: 10 in the Ochoco Monntains, 70:30 in the Aldrich Monntains, 50:50 in the ceirtral Blue

Mountains, 30:70 in the northern Blue Mountains, 10:90 in the Wallow'a Mountains, and 5:95 in central kkilio. \W also found that up to 12% of specimens from the east slope of the Rocky Mountains in Alberta are mostly yellow wdth only a slight orange flush, and that the frequency of yellow or near yellow butterflies increases southward in Montana (see Kohler, 2006). Because of these long, gradual dines between yellow and orange morphs, we suggested that the christina group should be taxonomically treated as subspecies of C. occidentaUs. Throughout the Great Basin and Intermountain regions, C. occidcntalis feeds primarily on legumes such as peas {Lathijiiis spp.) and false lupines {Thennopsis spp.). In shaiq> contrast, C. alexandra functions as a fully distinct biological species in these same regions, and specializes on highly to.xic legumes such as milk-vetches (Astragalus spp.) and locow^eeds (Oxi/tropis spp.).

Although Ferris (1987) reported C. gigantea from central Oregon, no actual populations have ever been found and verified. However, while we were examining some 900 specimens of C. occidcntalis across central Oregon to study the yellowy-orange dine discussed above, we obseiwed large numbers of specimens that

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205

Fig. I. (I) Colitis scmldcni scuihlerii. male dorsal, Colorado; (2) C. s. sciulderii. male ventral witli i^iarit diseal spots, Colorado; (3) C. v. scnddciii. lemale dorsal eream form, Colorado; (4) C. s. wiii/i. male ilorsal , Manitoba; (5) C. s. inaiji. female dorsal \ello\v form, Manitoba; (6) C. s. oracciuma . I lolohpe male dorsal, Wyoming; (7) C. s. gracciuwti. m;ile ventral vellow-green form with medium diseal spots. XWdming; (8) C. s. graccmma, male ventral with giant diseal spots. Wyoming; (9) C s. gracemma , Allohpe female dorsal cream lorm, Wyoming; (10) C. s. gracciuina, female sentral witli bieolored hindwing, WVoming; (11) C. s. grticriiniui . male ventral olive-green scuddeiii-]\\io form, Wyoming; (12) C. s. Iiiinvweii, male dorsal, WVoming; (13) C. .s. hiirrowcri , male ventral oli\e-green lorm wath giant diseal spots, Ws'oming; (14) C. s. hiiiToweii, male ventral vellow form with small diseal spots, W'voming; (15) C, .s: Imrnnvcii. lemale dorsal orange form, W\'ommg; (16) C. s. wai/i, male ventral dark orange lorm with small diseal spots, Alberta; (17) C. .s. kohlcri. Holohpe male dorsal, Montana; (18) Cf s. kohlcri. male ventral yellow-orange form with medium diseal spots, Montana; (19) C. s. kohlcri. AlloWpe female dorsal \elIow form. Montana; (20) C. s. kohlcri. female dorsal wliite form. Montana; (21) C. s. gigiiiitca. male dorsal, .-Maska; (22) C. s. gigimtcii. male \eutral orange form with large diseal spots, .Alaska: (23) C. s. gigantca. female dorsal white lorm. Alaska; (24) C. s. noricpticificii. I loloUpe male dorsal. British Co- lumbia; (25) C. s. noricpacifica . Allotype female dorsal, Ifritish Columbia.

had a phenotype virtually identical to th;it of C. gigantca. and thi.s phenotype appeans to be the basis for Ferris' report. Moreover, we tilso obsen’ed extreme phenotypes within these samples that were virtually identiciil to those of C. scudderii in the southern RocIsA' VIonntains and C, j)chdne skinneri Barnes in the central and northern Rocky Mountains. All of the Vaccinitim- Sali.x feeding species of CoUas are yellow in the males with no UV-reHectance like the West Coast forms of C. occidentalis. The existence of these intermediate

populations in central Oregon and the intermediate populations discnssetl below pro\lde much evidence for evolutionaiA' linkages among all three species complexes.

The above ohsenations have suggested to us a possible theoiA' of genealog\' and e\'olutioium' histon for the chn/sothemc species group. Based upon the cladistic analysis, a simple linear genealog)'' for the chn/sothemc subgroup appears to exist across Eurasia and North America heginning with C. croci’a in

206

Journal of the Lepidopterists’ SociETi’

southern Eurasia. Evolutionaiy steps in tliis genealogical sequence are (1) loss of the male androconical patch in C. din/sotheme in northern Eurasia, (2) reduction in discal spot size and black melanic scaling in C. eurijtheme in North America, (3) loss of orange coloration and UV-reflectance in C. philodice, and (4) loss of the double-ringed discal spot and black submarginal spots in West Coast forms of C. occidentaUs.

At this point, evolutionary patterns in the occidentaUs subgroup become very complicated. While the linear genealogy of the chnjsotheme subgroup could be viewed in a traditional dichotomous hierarchy of a standard cladistic analysis, the occidetitalis subgroup genealogy appears to be a multibranching or polychotomous pattern fjuite unlike the cladogram presented by Eerris (1993). Also, reticulate hybrid fusion or introgression appears to have played an important role in the evolution of this group oi CoUas.

An important theoretical concept is that of punctuated equilibrium (Gould & Eldredge 1977), the idea that taxa or populations are distributed through time as well as space, and share ancestor-descendant relationships as a consequence (see discussion in Hammond 1991). Snch relationships are never evident in a cladistic analysis with a nested dichotomous hierarchy. Instead, ancestral taxa are thought to produce large numbers of descendant taxa during an adaptive radiation in a multibranching or polychotomous pattern, while snniving largely intact and largely unchanged through long periods of time, often as relicts in more restricted and isolated refugia. Thus, C. occidentaUs is postulated to be the immediate ancestral parent species for three distinct daughter species; C. pelidne, C. scndderii, and C. alexandm.

Based upon our analysis of phenotypic v'ariation in central Oregon populations of C. occidentaUs, and the other intermediate populations discussed below, we suggest that both C. scndderii in the southern Rocky Mountains and C. pelid)ie in the central and northern Rock}' Mountains represent geographic isolates of ancestral C. occidentaUs populations from the Intermountain region. Such isolation events may have taken place in the late Miocene or Pliocene about 4-7 million years ago as conditions in the Rocky Mountains became cooler leading up to the glacial and interglacial periods of the Pleistocene. Such climatic shifts may have promoted a foodplant shift in Rocky Mountain populations away from legumes such as Lathy ms in favor of Salix and Vaccininm shrubs in subalpine environments.

Later during the Pleistocene, as C. scndderii spread northward through the central Rocky Mountains of

Wyoming and Montana and into Canada and Alaska, C. occidentaUs also spread into this region, initially hybridizing with C. scndderii to produce the modern gigantea phenotype. Eventually, Rocky Mountain populations of C. o. cUristina acquired full reproductive isolation from C. scndderii. The orange color and UV- reflectance of C. o. Christina may represent characters that were acquired in the Intermountain and northern Rocky Mountain regions from hybridization witli C. ennjtheme and C. rneadii Edwards, and these characters w'ere strongly selective in the northern Rocky Mountcuns and across Canada as a way to reproductively isolate C. o. cUristina from C. scndderii (Eerris 1993).

Still later, C. o. cUristina spread southward through the central Rocky Mountains of Montana and Wyoming, and into the southern Rocky Mountains of Colorado to speciate into the modern C. aJexandra, where it ecologically replaces C. occidentaUs. The further adaptive radiation of C. alexandra populations throughout the western Great Plains, Great Basin, and Intermountain regions appears to be of relatively recent origin, a response to the climatic diying and desertification of these regions during the Pleistocene that resulted in a large adaptive radiation of the legume genus Astragalus (Isely 1983).

We realize that the above evolutionary scenarios are highly speculative, but the existence of modern intermediate populations provides important supportive evidence. Such hypotheses are potentially testable as additional evidence becomes available in the future, perhaps using molecidar markers. Also, this theory serves as a background context for discussing the patterns of geographic variation and ecology within the C. scndderii complex below.

Subspecies Descriptions Colias scndderii ruckesi Klots

The taxonomic status of this subspecies is somewhat confused. Klots (1937) described this taxon from the south end of the Sangre de Cristo Range in the Pecos River drainage near Santa Ee, New Mexico. The type series was collected in 1935 and 1936. According to Klots’ description, this subspecies is distinctly different from the typical C. s. scndderii in Colorado and Wyoming. Diagnostic characters cited by Klots for C. s. nickesi include (1) larger size, (2) reduction or absence of the black discal spot on the dorsal forewing, (3) a broader black marginal border in the male, (4) a deeper yellow dorsal ground color, (5) heavier and more extensive black basal suffusion, and (6) a higher frequency of the yellow moq^h in females.

However, Eerris (1987) collected specimens of C. s. nickesi from the tyj^e locality later in the 1970 s, and was

Volume 62, Number 4

207

not able to distinguish these from tyj^ical C. s. scuddcrii in Colorado. It is possible that warmer climatie conditions during the 1930’s may have influenced the phenoty|3e, producing larger and darker colored butterflies compared to the 1970’s. We have only examined two specimens of C. s. nickesi, and have no new iiiformation to contribute regarding this (question. In general, peripheral isolates such as C, s. nickesi often exliibit some divergence, at least in gene and phenot)'|re frecpiencies, compared to more centrally located populations.

Colias scudderii scudderii Reakirt Figure 1, Tables 1 & 2

De.scription. Male (n = 108). Forewing length 22-2.5 nini, mean = 24 null. Dorsal ground color pale yellow. Black border ol forewng usuallv broad, sometimes narrow, with yellcjw veins. Small black discal spot of forewing usually prominent or reduced, rarely absent. Moderate to heavy black basal suffusion present on fore and hindwangs, Di,scal spot on dorsal bindwing usuallv yellow and faint. Black scaling in medial area of ventral forewing light to absent. Ventral ground color of liiudwing usually olive-green (79%), sometimes yellow-green (21%) watb lieavy black melauic .scaling. Discal .spot on ventral biiKhvang ringed with red, variably large (22%). medium (33%), or small (45%). A satellite spot is usually absent (73%), sometimes pre.sent (27%).

Female (n=32). Forewing length 2.3-26 mm, mean = 25 mm. Dorsal ground color variable, white (52%), cream (19%), or yellow (29%). Black border of dorsal lorewing is usuallv completely absent (78%), sometimes partialK present (19%4, and rarely fully developed (3%). Discal spot of dorsal hindwing usually yellow and faint, rarely orange. Ground color of ventral hindwing variable, usually oli\'c- green to vellow-green, sometimes orange. Other characters as in male.

Distribulion and ecology. This subspecies is common and widely distributed throughout the southern Rocky Mountains of Colorado, extending northward through the Medicine Bow and Laramie Mountains of southeastern Wyoming in Carbon, Albany, and Converse Counties. However, populations in the Sangre de Cristo Range of south-central Colorado extending southward through northern New Mexico are tentatively assigned to C. .s. nickesi as discussed above.

The habitat used by C. s. scudderii is more variable and extends over a much broadei' elevational gradient than suggested by Ferris (1987). The biitteiflly occupies open forests of (piaking aspen and conifers or open meadows within the forest at middle elevations, and subalpine or alpine meadows at high elevations at or above timberline. The high elevation populations appear to be feeding mostly on dw'arf willows {Salix spp.) as laiwal foodplants, but there are also numerous records of oviposition on Vaccinium caespitosum Michx. in Colorado (Scott 1986; Ferris 1987).

We have also obseiwed oviposition on Latlu/nis lanszwei'tii var. leucanthus Rydb. in Colorado. One of ns (PCH) found C. scudderii to be common at middle elevations on the west side of Core Pass in Routt

County during 1996. A large clear-cut was made in a diy, upland mixed forest of cpiaking aspen and lodgepole pine. LatJu/rus lanszwei'tii had densely colonized this open clear-cut, and was a major part of the ground cover. A large colony of abcmt 30^0 adults of C, scudderii was flying in this clear-cut, and at least three different females were observed ovipositiirg on the Lathyrus together with females of C. alexandra.

Discussion. Colias s. scudderii appears to be a highly specialized subspecies at least in morphology. The veiy small wing length combined with the monomoiyhic olive-green to yellow-green ground color on the ventral himKving ol males are strong diagnostic characters for this subspecies. In addition, it shows a high frequency of a small tliscal spot combined with no satellite spot on the ventral hindwang. In females, about 70% are white or cream in dorsal ground color and only about 30% are yellow. The black wing bender in females is nsnally absent or greatly reduced.

In spite of tliese specializations, tbe subspecies appears to be quite generalized in ecology with poly[4hagons laiwae, feeding on Salix, Vaccinium, and Lathyrus. In shaip contrast, three distinct species co- e.xist together in sympatry within the central and northern Rockv Mountains, with otlier C. scudderii subspecies using Salix exclusively as a lan al foodplant, C. pelidne using Vaccinium, and C. occidentalis or C, alexandra using legumes such as Lathyrus. Thus, in Colorado, C. s. .scudderii appears to be fully or partially using the foodplant niches of three different species in the central and northern Rockv Alountains, although the Lathyrus niche is mostly occupied by C. alexandra in much of Colorado (Hayes 1980).

As previously discussed, C. s. scudderii appears to be a sister species of C, pelidne, and both appear to have been isolated in the southern and north-central Rocky Mountains respectively from Intermonntain ancestral populations of C. occidentalis. Both switched away from the ancestral Lathyrus foodplants in favor ol' Salix and Vaccinium foodplants as climatic conditions became cooler in the Rocky Mountains prior to the Pleistocene glaciations. While isolated in the southern Rocky Alountains, C. s. scudderii has retained this evolutionaiy transition into modern times using diverse and multiple larv'al foodplants, while sympatric northern populations have evolved veiy narrow foodplant specializations as part of their speciation processes.

Colias scudderii Uinta Range population

An isolated population of C. scudderii occurs at high elevations in the Uinta Range of northeast Utah, including Summit, Daggett, Duchesne, and Uintah Counties. We have only examined a short series of 6

20S

fOURNAL OF THE LEPIDOPTERISTS’ SOCIETT'

males and 5 females from this population (Tables 1 & 2). Most of these specimens are veiy similar to the Colorado C. .s. scudderii in phenoty|De, but one male and one female are larger and similar in phenoty|3e to the Wyoming C. s. harroiveri Klots. We believe this population is transitional between the two subspecies.

Jacque Wolfe and Jack Hany (per. comm.) have made extensive ecological observations of the Uinta Range population. Most females oviposit on low Vaccinium species such as U caespitostnn growing in opeji conifer forests at high elevations. However, Jack Harry (per. comm.) also observed a local colony in a riparian zone along a creek where females were ovipositing on a tall Snlix species. Thus, the Uinta Range population appears to retain pol\qrhagous feeding habits like the Colorado populations.

In ecology, this population is intermediate between Colorado C. .scudderii and Wyoming C. pelidne skijvieri, and is mostly occupying the ecological niche of C. peUdne in the Uinta Range. However in moqohology, the population appears to be intermediate between Colorado C. .s. scudderii and Wyoming C. .s. harroweri.

CoUas scudderii gracemma Hammond & McCorkle, new subspecies Figure 1, Tables 1 & 2

De.scription. Male (n=73). Wings often elongate. Forewing length 22-27 nini. mean = 2.5 mm. Dorsal ground color pale yellow'. Black border of forewing variably liroad to narrow' with yellow veins. Small black discal spot of forewing oblong, prominent, rarely faint or absent. Moderate to heavy black basal suffusion present on fore and liindwings. Discal spot on dorsal hindwing usually yellow and faint, rarelv pale orange. Black scaling in medial area of ventral torewing light to absent. Ventral ground color of hindwing usually briglit yellow-green (74%), sometimes darker olive-green (26%), with heavy black melanic scaling. Discal spot on ventral hinclwing ringed with red, variabK’ large (55%), medium (25%), or small (20%). A satellite spot is usually present (84%), rarely absent (16%).

Female (n=40). Forewing length 24-28 mm, mean = 26 mm. Dorsal ground color variable, white (.30%). cream (38%), yellow (30%), or rarely with an orange flush (2%). Black border of dorsal forewing is usiuilly completely absent (50%) or partially present (32%), and sometimes fully developed (18%). Discal spot of dorsal hindwing variablv pale yellow to orange. Ground color of ventral hindwing blue-green to yellow-green, or bicolored darker orange in the medial portion of the wing with a paler blue-green submarginal band. Other characters as in the male.

Holotype. male, Wyoming, Johnson County, summit of Big Flom Mountains near Cloud Peak Wilderness Area, 13 July 2004, Terry Stoddard leg. The holoppe is deposited in the Oregon State Arthropod Collection, Oregon State Universit)', Corv'allis, Oregon, USA. Allotype, female, same data and deposition as holotype, but collected 19 July 2005. Paratypes. 65 males and 33 females, same locality as holotype. Disposition of paratypes as follows: 41 males and 20 females to the collection of Terry Stoddard, 18 males and 8 females to the collection of Steve Van Campen, and 6 males and 5 females to the collection of Paul C. Hammond.

Etymology. The name honors Grace Stoddard and Emma Van Camjoen who heljied collect and study this butterfly.

Distribution and ecology. This subspecies is narrowly endemic to the Big Horn Mountains in Wyoming, and is jrresently knowi only from the south end of the mountains in Johnson County near the Cloud Peak Wilderness Area. It occurs in broad, extensive wallow bogs or meadows at high elevations near the summit of the mountains. Females have been observed ovijrositing on a low-growang dwarf wdllow' {Salix sp.) in these bogs. At somewhat lower elevations in the Big Horn Mountains, there are extensive willow bogs dominated by a different sj^ecies of wallow that grows much taller into a large bush or small tree. C alias s. gracemma was never found in association with this tall wallow, and is veiy habitat limited as a consequence. Within the meadow and adjacent forest habitats, this sjoecies is symjoatric wdth three other species of C alias inclnchng C. j)elidne skinneri, C. occidentalis sacajawea Kohler, and C. philadice.

Diagnosis and discussion. This pojoulation is a cUstinctive isolate that is exactly intermechate between the Colorado C. s. scudderii and the more gigantea-\ike pojrulations to the north. Although Ferris (1987) kmew of this jropulation, he may not have seen sufficient material to recognize the following unique characteristics. Characters shared wdth C. s. scudderii include (1) males that are monomoiqhic green on the ventral hindwing, (2) females that are commonly white or cream (68%) in dorsal ground color, and (3) females in which the black wdng border is mostly reduced or comjoletely absent (82%). Characters shared with gigantea-\ike forms include (1) a high frequency of a large discal spot on the ventral hindwing (55%), and (2) a high frequency of a satellite sj40t (84%). In size, C. .s. gracemma is also intermediate between the southern and central Rocky Mountain subspecies of C. scudderii. Moreover, it should also be noted that extreme sjaecimens of C. s. gracemma are virtually identical in j^henotyjoe to either the Colorado C. s. .scudderii or the western Wyoming C. s. harroiveri Klots.

This subsjDecies does exliibit several unique features not found commonly in the other subsj^ecies. The wings are quite elongate compared to most other subspecies. Mides usually have a bright or vdvid yellow-green ground color on the ventral hindwing, in contrast to the darker olive-green ground color common in Colorado C. s. .scudderii. Females frequently are bicolored on the ventral hindwing, with an orange medial area contrasting with a j3aler blue-green submarginal area. Females in other subsjDecies of C. .scudderii also frequently show a darker, more brownish mechal area on the ventral hindwing, as do rare females of C. pelidne and C. occidentalism but these are rarely as contrasting as are the colors in some females of C. .s. gracemma.

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We suggest that C. s. graceinma represents a periplieral isolate of C. scuddehi populations that spread nortliward out of Colorado during early Pleistocene glaciations, initially hybridizing with ancestral populations of C. occidentalis to the north that produced the modern giganteadike phenoh^ies in northern populations.

Colias scudderii harroweri Klots Figure 1, Tables 1 & 2

Description. Male (n=55). Forewiiig length 23-28 mm, mean = 26 mm. tiorsal gronnd color pale yellow. Black border of forewing variable, narrow to broad, with yellow veins. Black discal spot of forewing variable, small and faint to large and round. .Vloderate to heav)' black basal suffusion present on fore and hindwings. Discal spot on dorsal hindwng faint vellow to orange. Black scaling in medial area of ventral forewing usually absent. Ventral ground color of hindwing variable oli\'e-green (2.5%), yellow-green (25%), or yellow (50%) with light to heavy black melanic scaling. Discal spot on \entral hindwing ringed with red, usuallv large to giant (65%i), sometimes medium (27%), or rarely small (8%). A satellite spot is usuallv present (75%), sometimes absent (25%).

Female (n=21). Forewing lengtli 26-29 miu, mean = 27 nun. Dorsal ground color usually yellow' (76%), rarely w'hite (5%d, cream (10%), or orange (9%). Black border of dorsal forewing is usualK- absent (.34%) or partially present (57%), rarely fully developed (9%*). Discal spot of dorsal hindwiug usually faint orange t(j dark orange. Ground color of ventral hiudwing yellow' to blue-green. Other characters as in male.

Distribution and ecology. Tliis subspecies is narrowly endemic to the mountains of western Wyoming in the Teton and Wind River Ranges of Teton, Sublette, and Fremont Counties. As we nari'owly define this taxon, it does not occur in the Yellowstone region of Wyoming and Montana, but is replaced northward by subspecies discussed below.

The butterfly is found in a variety of willow bog habitats at middle to high elevations in the mountains. These include riparian bogs along forest streams, extensive seepage areas in semi-open lodgepole pine forests, and extensive hanging bog meadows. Females oviposit on a dwarf willow species {SaJix sp.) i)i these bogs. This species is sympatric in the Wind River Range with C. pelidne, C. alexandra astraea Edwards, and C. philodice.

Discussion. This is the third subspecies or population that appears to be intermediate between the Colorado C, s. scudderii and the more gigoiitea-hke populations to the north. However, unlike the C. s. gracemma populations to the east in the Big Horn Mountains, these western populations appear to be more directly intergrading between C. .s. scudderii and C. .S', kohleri (described below) in Montana. Transitional characters include larger size, a mixture of green and yellow ground colors on the ventral hindwing of males, and a high frequency of the yellow morph in females. However, extreme specimens are still identical in phenotype to the Colorado C. .s. scudderii, particularly

at the south end of the Wind River Range in Fremont County.

One character that unicjnely distinguislies C. .s. harroweri is a high fretpiency of a giant discal spot on the ventral hindwang. This extreme character occurs in many populations of C. occidentalis and C. pelidue, but is usually (juite rare (1-5%).

In C. •s. scudderii, the frequency of giant spots is 12%, and is 23-31% in most other populations of C. scudderii throughout North America. However, this chaiacter reaches the highest frequency in C. s. harroweri at 50%, compared to a frecpiency of 27% in C. s. graceiwua .

Colios scudderii kohleri Hammond & McCorkle, new subspecies Figure 1, Tables 1 & 2

De.scription. Male (ii=.'360). Forewing lengtli 2.5-29 nnn, mean = 27 nnn. Dorsal ground color variable, pale to dark yellow, nsuallv niedinin yellow. Black border of forewng usuallv broad, rarely narrow, with yellow veins. Black discal spot of' torewdiig often large and prominent, round to oblong, rarelv faint or absent. Black basal suffusion on fore and hindwings usuallv moilerate to reduced, sometimes heavy-. Discal spot on dorsal himlwing pale vellow to orange. Black scaling in medial area of ventral forewing usnally absent to light, rarely moderate. Ventral gronnd color ol hindwang variable, usuallv y'ellow or orange, sometimes green. Black melanic scaling on ventral hindwing nsnally moderate to heaw, sometimes reduced. Discal spot on ventral Inndwing ringed with red, variablv large (4.3-54% ), medium (2.3-37%), or small (20-28%.). A satellite spot is usually present (7.3-83%), sometimes absent (17-27% ).

P'emale (n=180). Forevring length 26-30 nnn, mean = 28 nnn. Dorsal ground color variable, usually yellow (58-70%), sometimes white (8-22% ), or cream ( 10-,33%), rarely orange ( 1 %). Black border ol dorsal forewing variable, poorly developerl in some populations, well developed in other populations. Discal spot of dorsal hindw'ing variably pale to dark orange. Gronnd color of ventral hiiuKving \ariablv vehow, orange, or blue-green. Other characters as in the male.

Holotype. male. Montana, Beax erliead Gonntv', summit of tlie Pioneer Mountains, 21 July 2002, Paul C. Ilanimond leg. The holotv'j^e is deposited in the Oregon State Aithropod Gollection, Oregon State Universitv, Goivallis, Oregon, PhSA. .Mlotvpe. female, same data and depositif)ii as holotvpe. Paratypes. 93 males and .50 females, same localitv' as holotvpe. Disposition of paratvpes as follows: 13 males and 16 females to the collection of Tenv Stoddard, 45 males and 8 females to the collection of Steve Van Campen, 8 males and 7 females to the collection of Steve Koliler, 5 males and 4 females to the collection of David V. McGorkle, and 22 males and 15 females to the collection of Paul G. Hammond.

Etymology. The uaiue honors Steve Kohler, who has made an immense contribution to the studv of Montana butterflies.

Distribution and ecology. This subspecies as we define it here is wadely distributed in the central Rockv Mountain region, from the greater Yellowstone ecoregion in northwest Wyoming north throughout most of western Aloutana to Flathead CouuU', and west t(i the west slope of the Bitterroot Range in Lemlii County, Idaho. Ferris (1987) has reported a record Irom Blaine County in south-central Idaho, but we have not been able to verify this record. Earlier I'eports

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(Ferris 1987) from central Oregon are probably niis- iclentified C. occidcntahs.

This subspecies occupies extensive, open boggy meadows with dwarl willows, either at middle elevations in hanging bogs on mountain slopes anti in riparian zones along creeks, or in snbalpine meadows at the higher elevations in the mountains. At the txqae localitv in the Pioneer Mountains, there are actually two distinct species ol dwarf willows growing together in sympatry; one with green leaf petioles and haiiy leaves, and one with red petioles and smooth leaves. The females of C. s. kohleii at this locality were highly selective in their choice for opposition, and were obsen^ed to oPposit only on the red petiole-smooth leaf tvpe of \Pllow. This Salix might be either S. hoothii Dorn or S. plaiiifolia Pnrsh.

Diagnosis and discussion. This subspecies is extremely similar in phenotvpe to common forms of C. occkJentalis across central Oregon. In fact, we know of no diagnostic character that consistently separates the two species. On average, males of C. s. kohleri show reduced black basal suffusion on the dorsal wdngs compared to males ol C. occiclentalis, but there is much overlap between them. Also, C. s. kohleri shows a much higher frequency ol giant discal spots on the ventral hindwing (23-36%) compared to C. occideutalis (1-5%).

There is a slight average difference between the two species in the wing pattern of females on the dorsal forewing. In females with partial or full development ol the black wing border, C. scudderii usually exliibits a stronger development of the inner portion of the border that appears as a thin, black line, wiiile the outer portion is often obscure or completely absent. This development is most often exactly reversed in females of C. occideutalis. Again, however, this character is not consistently different between the two species, and immaculate females are essentially identical.

We suggest that C. s. scudderii spread northward out of Colorado during early glacial periods of the Pleistocene, eventually hybridizing with ancestral populations of C. occideutalis in the central Rocky Mountains of Montana. This reticulate hybrid fusion resulted in the modem gigautea-like phenoppe of C. .s. kohleri that closely resembles the ancestral phenot)q3e of C. occideutalis, but retains the specialized lamil feeding niche on dwarf willows of the C. .s. scudderii parent. Eventually, reproductive isolation betw^een the two species was attained, perhaps wdth help from the orange- UV coloration acquired later by C. occideutalis males in the central-northern Rocky Mountain region. Foodplant incompatibility between the legume-feeding and willow-feeding niches was probably the drmng selective force that promoted eventual reproductive

isolation and full speciation.

There is some geographic variation in populations of C. .s. kohleri that is probably of evolntionaiy significance. The most variable populations are found at the t)q)e locality in the Pioneer Mountains of Reaverhead and Deer Lodge Counties, Montana (Tables 1 & 2). Consequently, this region is thought to be the historical center of origin for the original hybridization between C. scudderii and C. occideutalis, and the original point of origin for C. s. kohleri. These populations still exhibit a relatively high frequency oi scuddcrii-\\ke green colors on the ventral hindwang of males, 24% yellow-green and even 4% olive-green. Also, females are mostly immaculate (71%), and only about 29% show partial or full development of the black wing border.

In shapD contrast, the populations of C. s. kohleri in the greater Yellowstone ecoregion are highly divergent from the original scuddcrii-\ike phenotyjie (Tables I & 2), even though they are geographically closest to the scudderii-like C. s. gracemma and C. s. harroweri populations in Wyoming. Roth the Absaroka Range population in Park County, Wyoming and the Centennial Range population in southern Beaverhead County, Montana and adjacent Fremont County, Idaho are almost monomoq:)hic for yellow or orange colors on the ventral hindwing of males (99-100%), and very rarely show green colors (1%) of the .scudderii ty^^e. Also, females show a much higher frequency of partial or full development of the black wing border (59-78%). For these reasons, we believe the Yellowstone region populations are of relatively recent origin, possibly spreading into this region since the last Pleistocene glaciation. They appear to have had little genetic contact with the older C. s. harroweri populations to the south in the Teton region.

Northward from the Pioneer Mountains, populations of C. .S', kohleri also show reduced variation, and are mostly monomoqDhic yellow or orange on the ventral hindwTiig in Granite, Missoula, Lake, and Flathead Counties. We have seen only a few specimens from the east slope of the Rocky Mountains in northern Montana, but these closely resemble the Canadian C. s. mai/i Chermock. A population in Lewis and Clark County appears to be intermediate between C. s. kohleri and C. s. tuaiji, but the population in Glacier County belongs to this Canadian subspecies.

During later periods of the Pleistocene, C. s. kohleri appears to have produced four distinct evolutionai'y lineages of the gigautea-type in Canada and Alaska. These include the following C. s. uiaiji to the northeast in central Canada, C. s. gigautea Strecker in the sub- arctic north, C. s. iuupiat Harry in the far ai'ctic north of Alaska, and an unnamed segregate in the northwest.

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The evolutioiiaiy histoiy of these four northern segregates appears to he intimately connected with the histoiy of Pleistocene glacial and interglacial periods in Canada and Alaska.

Colias sctidderii mayi Cherniock & Chermock Figure 1, Tables 1 & 2

Description. Male ta=50). Wings usually elongate, Forewiug length 2.5-30 rum, mean = 28 mm. Dorsal ground color usually medium yellow, .sometimes pale or dark yellow. Black border of lorewing usually broad, rarely narrow, with yellow veins. Black discal spot of forewing usually large and prominent, round to oblong, sometimes reduced and faint. Black basal suffusion on fore ami hindwangs greatly reduced or completely absent. Discal spot on dorsal hindw-ing usually pale to medium orange, sometimes hunt yellow. Black scaling in medial area oi ventral lorewdng usually absent. Ventral ground color of hindwing yellow or orange. Black melanic scaling on ventral hindwing usuallv reduced or absent, but often heavier in Rocky Mountain populations. Discal spot on ventral hindwing ringed with red, variably large (37-.3S%), medium (2S-,32%), or small (.31-.34%). A satellite spot is usually present (66-89%), .sometimes absent ( 1 1-,34%.).

Female (n=24). Forewing length 26-32 nun, mean = 29 mm. Dorsal ground color usually yellow, sometimes orange in western populations, white or cream in eastern populations. Black border of dorsal forewing variable, usually absent (41-.57%) or partialh’ present (29—41%), rarelv fullv developed (14-18%), Discal spot of dorsal hindwing pale to dark orange. Ground color of ventral liindwing yellow to orange. Other cliaracters as in male.

Distribution and ecology. This subspecies is widely distributed across central Canada. It extends from southeast Manitoba west across central and northern portions of Manitoba, Saskatchewan, and Alberta to the Rocky Mountains, and southward along the eastern slope of the mountains to Glacier County, Montana. There is an isolated population in the Cypress Hills of Saskatchewan (Layberiy ct al. 1998). Northward, the distribution extends into the southern portions of the Northwest Territoiy around the Great Slave Lake. Westward, it extends throughout northeast British Columbia, and southward through the drainage of the Fraser River valley to about Jesmond, British Columbia (Guppy & Shepard 2001). In ecology, C. s. mat/i occupies willow bogs in the taiga forest zone across central Canada, and in more isolated bogs further south in the mixed conifer-aspen parkland zone (Bird et al. 1995; Layberiy etn/. 1998).

Discussion. Colias s. inai/i is the most divergent subspecies of C. scuddeiii, both from the Colorado C, s. sciuldeiii and from West Coast forms of C. occidentalism and is recognized by many distinctive characters. These include (1) veiy large size, (2) elongate wings, (3) deeper yellow dorsal ground color, (4) little or no black basal suffusion on dorsal wings, (5) often reduced or absent black melanic scaling on the ventral hindwing, (6) monomorphic yellow or orange ground color on the ventral hindwing, and (7) nearly monomoqihic yellow females.

Ferris (1987) failed to recognize the distinctive

dillerences between this sul)species and the northern sub-arctic C. .s. gigantea, apparently because of the clinal intergradatiou Iretween the two subspecies in northern Manitoba. However, Masters (1970) correctly identified the above distinctions, and recognized C. s. mai/i as an important evolutionaiy segregate. There is some minor geographic variation across Canada. Populations in the Rocky Mountains tend to show more black melanic scaling on the ventral hindwing compared to more eastern populations, and are nearly mouomoqrlnc for yellow females. Orange females are somewhat frequent in Rocky Mountain populations (12%), and may represent a residue from past hybridization with orange lorms ol C. occidentalis. These are usually mis-identified as females of C. o. Christina.

As discussed by Masters (1970) and Ferris (1987), there is an apparent zone of clinal intergradation with C. s. gigantea in Manitoba, resulting in a higher trecpiency of white or cream females in eastern populations. Nevertheless, the hybrid sntnre zone between the two subspecies appears to be rather abrupt across much of Canada, similar to the abrupt suture zones oi Limei}itis ai'themis/astijanax (Nymphalidae) and Paj)iIio gjaucus/canadensis (Papilionidae).

We suggest that C. s. niaiji evolved as a northeastern segregate from C. .s. koJderi in the taiga zone of central Canada centered in Manitoba during the Pleistocene. Its distribution has probalrly expanded and contracted periodically with the climatic lluctuations ol the Plei,stocene, following the north and south movements ol the taiga zone on the nortliern Great Plains. Dnring periods of glacial mirdma, the distribution probably spread southward on the plains of eastern Montana and North Dakota, and moved north again Irack into Canada during warm interglacial periods. We suspect that C. .s. mai/i spread westward to the northern Rocky Mountains of Alberta and into British Cohunbia more recently since the retreat of the last glacial maxima about 12, ()()() years ago.

Colias scudderii gigantea Strecker Figure 1, Tables 1 & 2

De,scription. Male (n=32). Forewing length 24-28 min, mean = 26 mm. Dor.sul ground color pale yellow. Black border of forewing usually broad, rarelv narrow, with yellow veins. Black discal spot of forewing variable, round to oblong, sometimes large and prominent, often reduced and faint. Black basal suffusion on fore and hiiKlwings usually moderate, sometimes liglit to heavy. Discal spot on dorsal hindwing pale yellow to orange. Black scaling in medial area of ventral forewing light to heavy, sometimes absent. Ventral ground color of hindwing usuallv yellow or orange, rarely green. Black melanic scaling on ventral hindwing moderate to heavy. Discal spot on ventral hindwing ringed with red, variably large (25-.35%), medium (33-45%), or small (20—42%). A satellite spot is usually present (80-92%), sometimes absent (8-20%).

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Female (n=16). Forewing length 25-29 nini, mean = 27 mni. Dorsal ground color usually white (67-70%) or cream (30-33%). Black border of dorsal forewng variable, often absent or partially present, sometimes fully developed. Discal spot of dorsal hindwing pale cream to orange. Ground color of ventral hindwing yellow, orange, or blue-green, often with veiy' heavy black melanic scaling. Other characters as in male.

Distribution and ecology. As we narrowly define this subspecies, it is limited to true arctic or sub-arctic regions of Canada and Alaska. It is widely distributed throughout much of Yukon and Alaska extending to the south slopes of the Brooks Range, the Richardson Mountains, and west to the Seward Peninsula. Eastward, it extends to the Arctic Ocean in the Alackenzie River valley, the Great Bear Lake, and probably in the tnndra-taiga ecotone regions of Northwest Territorx' to Hudson Bay. It then occurs to the southeast along the shores of Hudson Bay in Manitoba to the west shore of James Bay in Ontario.

C. .S', oigontea occupies willow bogs in low arctic tundra and semi-forest taiga. Females have been obseiwed ovdpositing on Salix reticulata L. at Churchill, Manitoba (Ferris 19S7). This subspecies appears to be particularly adapted to open tundra habitats, compared to the more taiga zone willow bogs of C. .s. mayi. However, in central Alaska near Fairbanks and across central Yukon, it does occupv a more taiga semi-forest habitat.

Discussion. In shaip contrast to C. .s. uiayi, C. s. gigantea has e.xperienced veiw little moiphological divergence from C. s. kohleri and central Oregon forms of C. occidentalis. In fact, the only real difference among these taxa is the monomoqrhic white or cream forms of the female in C. s. gigantea. There is some range of variation in this subspecies. We have not seen what we would regard as a true yellow female form, but the cream form is frequently dark enough to approach yellow. Also, some females show a tinge or flush of orange on a white or cream background. Butterflies from low elevations in central Alaska near F airbanks ai'e often much larger in size like C. .s. mayi, wdth a male forewTUg length of 27-29 mm. However, these still show the characters of t)qrical C. s. gigantea.

A major problem with this subspecies is that there has long been confusion wdth arctic populations of sympatric C. peliclne. The latter is more narrowly limited to higher elevation montane habitats in the Mackenzie, Ogilvie, Richardson, and Brooks ranges of northwest Canada and Alaska. There appears to be considerable overlap in characters between the two species, possibly because of past hylrrid introgression. We believe that Ferris (1987) actually illustrated the male and female of C. peliclne from the Ogilvie Mountains (his Figures .39-42), while his Figures 4.3-44

illustrate a tyjrical male of C. s. gigantea from the Seward Peninsula. In general, males of the latter species closely resemble central Oregon forms of C. occidentalis, often with a strongly developed black discal spot on the dorsal forewing and a broad wing shape. By contrast, males of C. pelidne always have a very small, faint black discal spot with rather short, stubby wings. However, the most consistent difference between the two species may be size. Males of C. pelidne are consistently smaller with a forewdug length of 22-24 mm (mean = 23 mm), while sympatric males of C. s. gigantea nsnally have a forewing length of 24-26 mm (mean = 2.5 mm).

We suggest that C. .s. gigantea evolved as a far northern segregate from C. .s. kohleri in the tundra-taiga zone of Alaska and Yukon during the Pleistocene. As with C. .s. mayi, its distribution probably expanded and contracted periodically with the climatic fluctuations of the Pleistocene. During the last glacial maxima about 18,0()0 years ago, its distribution was probably confined to non-glaciated refugia in Yukon and Alaska (see discussion in Laybeny et al. 1998). As the glacial ice sheets began to retreat across northern Canada about 10, ()()() years ago, C. s. gigantea spread eastward across Northwest Territory following the tundra habitat. It probably reached Hudson Bay during the warm hypsithermal period about 6000 to 9000 years ago (Laybeny et al. 1998). At the same time, C. s. mayi was probably spreading northward into Manitoba from its glacial refuginm on the northern Great Plains. Thus, the modern clinal intergrade zone in Manitoba between the two subspecies appears to be of veiy recent origin, taking place during this lyqrsithermal period.

An interesting biogeographic issue concerns biotic dispersal across Beringia between North America and Eurasia as cfiscussed by Lafontaine & Wood (1988) and Laybeny et al. (1998). Wolfe & Leopold (1967) have discussed the histoiy of biotic interchange between Eurasia and North America during the Tertiary. Land bridges between the continents existed over Beringia and a North Atlantic connection over Greenland and Iceland up to the middle Miocene period, and then over Beringia through the Pliocene period. Tropical and subtropical biotas were exchanged between the continents through the Oligocene and Eocene periods about 25-40 million years ago, and warm temperate biotas were continuous across the continents during the early to middle Miocene about 15-25 million years ago.

However, all land connections may have been broken by seaways during the late Miocene about 7-15 million years ago as climatic conditions became cooler at high latitudes. This allowed boreal or taiga type conifer forests to evolve independently in Eurasia and North

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America (Wolfe & Leopold 1967). Tlie Beringia connection between Alaska and Siberia was re- established in the Pliocene about 3-7 million years ago, allowing a new intercliange of a cold-adapted tnndra biota to spread across the northern portions of the continents. However, some autliors such as Petrov (1967) believe this Beringian connection was mostly broken during the Pleistocene. During periods of glacial maxima, nincli of Beringia was covered with either glacial ice sheets or cold, xeric grasslands rather than shrub tnndra, while the Bering Strait seaway separated Alaska and Siberia during warm interglacial periods oi the Pleistocene (Hopkins 1967).

These considerations are directly relevant to the inter-change of Lepidoptera populations between Eurasia and North America snch as species of Colias. The Vncc/'/dn/n-feeding group of CoUas has clearly dispersed back and forth between North America and Eurasia on at least three separate occasions. The ancestral C. pelichie is thought to have originally dispersed from Alaska into Siberia in the early Pliocene, producing the C. palacno radiation across the entire boreal region of Eurasia. This species then dispersed back across Beringia into North America to produce the modem C. chippewa, and this latter species dispersed a third time from Alaska into Siberia to produce C. c. goiuojtniovae Korshunov. All of these dispersal events nuist have taken place in the Pliocene or early Pleistocene about 1-7 million years ago if Hopkins ( 1967 p. 472), Petrov ( 1967), and others are cori'ect that the Beringian connection between the continents was mostly broken during the late Pleistocene with respect to shrub tundra.

In shai'p contrast, C. sciidderii is widely distributed throughout most of Alaska today, extending west to the Seward Peninsula. Yet it has never been able to disperse across Beringia into Siberia. Certainly the boreal willow bog-tnndra habitat is widespread across the nortliern regions of Eurasia. This evidence suggests that Petrov (1967) may be correct. Colias sciidderii probably evolved in North America during the middle Pleistocene, and reached Alaska too late to snccessfully disperse acnjss Beringia into Eurasia. The C. j)clidne adaptwe radiation is much older, and had no problem in dispersing repeatedly betvv'een the continents dining the Pliocene or early Pleistocene.

Colias sciidderii inupiat Hany

De.scription ( from Hum' 2007). .Vlale (n=43). Furewing length 20-2.5 111111, mean ~ 2.3 mm. Dor.sal ground color pale yellow. Black liorder of i'orewing u.siiallv medinm broad witii yellow vein.s. Black discal spot of torewing usually reduced to absent. Black basal suitusioii on tore and liindwings moderate to heavy. Discal spot on dorsal hindvving pale yellow to orange. Black scaling on \'entral forewiiig light to moderate. Ventral hindwing ground color yellow-

orange, usually wath strong green over-scaling. Black melanic scaling on ventral hindwing moderate to heaw. Discal spot on \entral hindwing ringed vidth red, sometimes with a satellite spot.

Female (n=17). Forewing length 2,3-27 mm, mean - 25 mm. Dorsal ground color usuallv yellow or cream. Black border of dorsal forewing variable, often alisent or partially present, sometimes fnllv dev'eloped. Discal spot of dorsal hiiulwing orange. Otlier ciiaracters as in male.

Distribution anti ecology. Thi.s .subspecies was recently described from extreme northern Alaska north of the Brooks Range (Harrv 2007). It occupies tlie foothills and coastal plain betvv'een the mountains and the Arctic Ocean. Although collection records are conhned to the vdcinitv of the Dalton Higlivv'ay, the subspecies is probably widely distribntetl across northern Alaska betvv'een the Brooks Range and Arctic Ocean.

Harn' (2007) describes the habitat as low boggv' tundra, and in bogs along small streams in the Sagvv'on Hills. Females were obseiwed ov'ipositing on SV/Z/.v Janata L.

Di.sfussion. Colias s. inupiat differs from C. s. gigantea in ven' small size, more greenish ov'er-scaling on the ventral hindvv'ing, and monomorphic yellow or cream females. Both snlispecies appear to be northern segregates deriv'ed from C. .s. kohleri, which is polv'inoiyhic vvitli yellow, cream, and white females.

Hopkins et al. (1982) illustrate the known e.xtent of glaciation in Beringia during the last glacial maxima about 20,000-14,000 years ago. The combined Lanrentide and Cordilleran ice sheets covered most of Canada extending through southern and eastern Yukon, and the St. Elias and Alaska Ranges vv'ere heavily glaciated across southern Alaska. The Brooks Range was also heavily glaciated across nortliern Alaska. However, most of western and central Alaska was non- glaciated, extending east through the Yukon River drainage of western Yukon. The arctic coastal plain north of the Brooks Range was also non-glaciated, as vv'as the Beringian land bridge connection with Siberia. As discussed by Hopkins et aJ. (1982), most of this land is thought to have been cov'ered with a veiw’ .xeric arctic steppe or mammoth steppe composed of bnnchgrasses and xeric herbs snch as Aiieniisia spp. (Asteraceae). Such steppes supported herds ol large mammals snch as the vv'oollv mammoth. The mesic birch-heath shrub tnndra with dwarf willows is thought to hav'e been veiy narrowly restricted at this time to the edge ol montane glaciers vv'here moisture from melting ice was available. This is why C. sciidderii was probably unable to spread w'estw'ard across the mannnotli steppes of Beringia into Siberia during the Pleistocene.

Thus, we suggest that ancestral populations of C. s. kohleri with polvinoiplhc females spread northw'ard into Alaska from the Rockw Mountains during a warm

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interglacial period, possibly during the Sangamon Interglaciation about 120,000 years ago (Hopkins et al. 1982). During later periods of glaciation, separate populations became isolated north and south ol the Brooks Range. Populations in the Yukon River drainage of central Alaska and eastern Yukon evolved into the modern C. s. gigantea with inonomoqYhic white or cream females, while populations on the arctic coastal plain north of the Brooks Range evolved into the modern C. s. inupiot with monomoqrhic yellow or cream females. Of course, we have no way to know the e.xact timing of these events, since at least four major glacial-interglacial cycles are known to have impacted Beringia over the past 400,000 years (Hopkins et al. 1982). It is quite possible that C. s. iniipiat has been isolated on tlie arctic coastal plain for a veiy long time, sniwiving throngh a number of Pleistocene climatic cycles.

CoUas scudderii nortepacifica Hammond & McCorkle, new subspecies Figure 1

Description. Male (n=2). Forewing length 2.5-26 inni. Dorsal ground color pale yellow. Black border of forewing broad with yellow veins. Black discal spot of forewng large and prominent, round to oblong. Back basal suffusion on fore and hindwdngs very heavy. Discal spot on dorsal hindwang pale yellow to orange. Black scaling in medial area of ventral forewing light to absent. Ventr;il ground color of hindwing yellow to pale yellow-orange. Black melanic scaling on ventral hindwang ver)' heavy. Discal spot on ventral hindwing ringed with red, variably small to large. A satellite spot is variably present or absent.

Female {n=l). Forewing length 27 mm. Dorsal ground color yellow. Black border of dorsal forewing fully developed, with the inner border forming a thin black line and the outer border faint and dusky. Discal spot of dorsal hindwing orange. Ground color of ventral hindwing yellow-orange with veiy' heavy black melanic scaling. Other characters as in male.

Holotvpe. male. British Columbia, Nimpo Lake, 28 July 1962, A.L. Alderman leg. The holotvyie is deposited in the Oregon State Arthropod Collection, Oregon State Univ'ersity, Corvallis, Oregon, USA. AllotyiJe. female, same data and deposition as holotype. ParaCpe. male, British Columbia, Tatla Lake near Hwy. 20, 2.3 July 1981, Jon and Sigrid Shepard legs., deposition as holotype.

Etymology. The name refers to the Pacific Northwest.

Distribution, diagnosis and discussion. We have iclentifiecl a veiy unusual isolate of C. scudderii that appears to be narrowly endemic to a remote region of southwest British Columbia. At present, it is only known from the three ty|3e specimens. These were originally identified as C. occidentolis based upon the very heavy black basal suffusion on the dorsal wings, and the heavy black melanic scaling on the ventral hindwang. However, these specimens differ from the typical form of C. occidenfalis that is nearly parapatric in the drainage of the lower Fraser River valley by having a pale yellow or yellow-orange ground color on the

ventral hindwing. The female has the black wing border of the C. scudderii type in which the inner border is present as a thin, black line, while the outer border is dusky and obscure. In shaq) contrast, C. occidentalis has a dark orange ground color on the ventral hindwing, and the female wing border is usually more solid black at the outer border and more dusky and obscure at the inner border.

The parapatric C. s. maiji in the drainage around the middle Fraser River valley is also distinctly different from this new subspecies. It often has a dark orange ground color on the ventral hindwing, often with greatly reduced Irlack melanic scaling. In addition, it differs shaq^ly from both parapatric C. occidentalis and C. s. nortepacifica in having little or no black basal suffusion on the dorsal vrings.

At present, this new subspecies is only known along Highway 20 from Tatla Lake northwest to Nimpo Lake just east of Tweedsmuir Provincial Park. As discussed by Guppy & Shepard (2001), most of British Columbia was covered with glaciers during the last glacial maxima about 18,000 years ago. However, there must have been a non-glaciated refugium in southwest British Columbia at this time, probably in the rain shadow of the Coast Mountains east of Tweedsmuir Provincial Park within the larger Chilcotin River region. A number of distinctive butterfly taxa are endemic to this region and to south-central British Columbia in general, including C. alexandra columbiensis Ferris (Pieridae), Speijeria aphrodite Columbia Hy. Edwards, S. callippe chilcotinensis Guppy & Shepard, S. mormonia jesmondensis dos Passes & Grey, a form of S. atlantis beani Barnes & Benjamin ( = S. hesperis of some authors), and a very dark melanic form of S. zerene picta McDunnough (all Nymphalidae).

We suggest that C. .s. nortepacifica evolved as a fourth segregate from the Rocky Mountain C. .s. kohleii in the upper Pacific Northwest during the Pleistocene. However, while both C. s. maiji and C. .s. gigantea were able to achieve wide and successful distributions during the Pleistocene, C. s. nortepacifica was nearly exterminated by the widespread glaciations in British Columbia. Only a few populations appear to have survived into the modern day as relicts within a non- glaciated refugium. The subspecies may be quite sedentary with limited dispersal abilities. By contrast, C. s. maiji is thought to have entered British Columbia quite recently from Alberta, first moving west through the Peace River drainage, extending northwest-ward towards Yukon, and southward through the Fraser River drainage to about Jesmond around 10,000 years ago as the glaciers retreated from central British Columbia. There is no evidence at this time of any genetic contact

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or intergradation hetw^een C. s. maiji and C. s. nortepacifica .

Acknowledgements

We particulai'ly want to acknowledge Teny and Grace Stod- dard, Steve and Emma Van Cktmpen, Steve Kohler, and Jon and Sigrid Shepard for their extensive field sampling efforts that helped Form tlie basis of tliis study. We also thank Chris Mar- shall for use of the Oregon State Arthropod Collection at Ore- gon State University. Jacajne Wolfe and Jack Harn- provided lielpfnl ecological information, while Jeff Miller assisted with photographv.

Iaterature Cited

Bird, C.D., G.J. Hilciiie, N.G. Kondla, E.M. Pike, & F.A.f I. Sper- ling. 1995. Alherta butterflies. The Provincial Mnseuni of Al- berta, Edmonton, Alberta. 349 pp.

Eerris, C.D. 1987. A reNasion of the North American SV;/i.r-feeding Colias species (Fieridae: Coliadinae). Bull. Allyn Mus. 112: 1-25.

. 1993. Reassessment of the Colias alexandra group, the

legume-feeding species, and preliminaiy' ciadistic analysis of the North American Colias (Fieridae: Coliadinae). Bull. Allyn Mus. 138:1-91.

Gould, S.J. & N. Eldredge. 1977. Punctuated eijuilibria: The tempo and mode of evolution reconsidered. Paleobiology 3: 1L5-151.

Guppy, C.S. & J.tl. Shep.xrd. 2001. ButterHies of British Columbia.

II BC Press, Vancouver, British Columbia. 414 pp.

II.vmmond, P.C. 1991. Patterns of geographic variation and evolution in pol\'t)-|ric hutterllies. [. Res. Lepid. 29: .54-76.

& D.V. McCorkle. 2003. A new desert subspecies o^i Colias oc-

cklentalis (Fieridae) from southeastern Oregon. J. Lepid. Soc. 57: 274-278.

Harry, J.L, 2007. A new subspecies oi Colias giganlea from arctic Alaska (Fieridae). The Taxonomic Report 6: 1—4.

Hayes, J.L. 1980. Some aspects of the biology of the developmental stages of Colias alexandra (Fieridae). |. Lepid. Soc. .34: .34.5-.352, Hopkins, D.M. 1967. The Cenozoic history of Beringia- a s)mthesis. Pp. 451-484. In D.M. Hopkins (ed.). The Bering Land Bridge, Stanford University Press, Stanford, California.

Hopkins, D.M., J.V. Ma'ithews, JR., C.E. Sc:iiweger, & S.B. Young (eds.). 1982. Paleoecolog)' of Beringia. Academic Press, New York. 489 pp.

ISELY, D. 1983. Astragalus {IjCguminosae: Papilionoidaeae) 1.: Keys to United States species. Iowa State Journal of Research .58: 1-172.

Klots, A.B. 1937. Some notes on Colias and Brenthis (Lepidoptera, Fieridae and Nymplialidae). J. N.Y. Ent. Soc. 60: ,311-3.33.

Kohler, S. 21)06. Colias christina sacajawca Steve Kohler, new sub- species. In J.A. Scott (ed.). Taxonomic studies and new taxa of North American hutterilies. Papilio (new series) 12: 8-10.

Lafontaine, J.D, & D.M. Wood. 1988. A zoogeographic analysis of the Noctuidae (Lepidoptera) of Beringia, and some inferences about past Beringian habitats. Mem. Ent. Soc. Canada 144: 109-12,3.

Layhem', R.A., P.W. Hall & J.D. Lafontaine. 1998. The butterflies of Canada. University of Toronto Press, Toronto, Canada. 280 pp.

Masters, J.H. 1970. Concerning Colias christina mai/i Chermock & Chermock. J. Res. Lepid. 9: 227-232.

Petrov 0.,M. 1967. Paleogeography of Chukotka during late Neo- gene and Quaternary time. Pp. 14-1-171. In D.M. 1 lopkins (ed.), Tlie Bering Land Bridge, Stanford University Press, Stanford, California.

Scott, J.A. 1986. The butterflies of North America. Stanford Uni- versitv Press, Stanford, California. 583 pp.

Verhulst, J.T. 2000. Les Co/w.s du Globe: monograph of the genus Colias. Goecke & Evers, Keltern, Germany. 571 pp.

Warren, .A,. D. 2005. Lepidoptera of North America 6. ButterHies of Oregon: Their taxonomy, distribution, and biology. Contributions ot the C.P. Gillette Museum of Arthropod Diversity. Colorado State Universits', Eort Collins, CO. 408 pp.

Wolfe, J.A. & E.B. Leopold. 1967. Neogene and early Quatemaiy vegetation of northwestern North America and northeastern Asia. Pp. 193-206. In D.M. Hopkins (ed.). The Bering Land Bridge, Stanford University Press, Stanford, California.

Received for publication 25 Januanj 2007: revised and accepted 6 March 2008.

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Journal of the Lepidopterists' Soeietij 62(4), 2008, 216-231

NEARCTIC EUCOSMINI (TORTRICIDAE) ASSOCIATED WITH PELOCHRISTA OCCIPITANA (ZELEER) AND EUCOSMA BIQUADRANA (WALSINGHAM): TWO NEW SYNONYMIES

AND EOUR NEW SPECIES

Donald J. Wright

3349 Morrison Ave., Cincinnati, Ohio 45220-1430, USA; email: vvrightdj@fnse.net

ABSTRACT. Pelochr'mta occipHana (Zeller), a species inisidentified in North American collections for more tlian eighty years, is reviewed, illustrated, and reassigned to Eucosma Hiibner, Two new species, Pelochrista aiiisliei and Pelochiista kingi, are described from material formerly determined as occipitana. Eucosma mediosfriata (Walsingham), Pelochrista reversana (Kearfott), and Pelochrista palpana (Walsinghain) are in- terpreted as close relatives of these new taxa, based on male genitalia, and mediostriata is transferred to Pelochrista. Pelochrista gilUgani, a new species with affinities to )>alpaua. is described irom Utah. Pelochrista fuscosparsa (Walsingham) is also reviewed, and a previonsly unrecognized species from California with similarities to both fu.scosparsa and mediostriata is described as Pelochrista fuscostriata. Finally, Pelochrista paloii- sana (Kearfott) and Pelochrista tahoensis (Heinrich) are recognized as junior synonyms o( Eucosma bkniadrana (Walsingham), and an account of the superficially similar Eucosma shastana (Walsingham) is included for comparison. Illustrations are provided of the adults and genitalia of the above mentioned species, and distributional information is reported. Lectotvpes are designated for the five species described Ivy ^^''alsing- ham.

Additional key words: fuscosparsa . mediostriata. palotisaiia. palpana. reversaiia. sha.stana. tahoensis.

Paedisca occipitana Zeller was described in 1875 troni a single male specimen collected by G. Beltrage in Te.xas. It was later transferred to Encosma Hiibner by Eernald [1903], and that is where it resided at the time of Heinrich's (1923) revision of Nearctic Encosmini. The holoHpe, which had been retained by Zeller, passed by way of the W'alsingham Collection to the Natural Histoiw Mnsenm, London (RMNII), and Heini'ich did not have an opportnniR' to examine it. As a result, he mistakenly identified as occipitana a specimen in the United States Mnsenm of Natural Histow (USNAI) that had been collected by C. N. Ainslie in New Alexico. In the eighty some years that have elapsed, Heinrichs illustration (1923, Eig. 226) of that male's genitalia has been the basis for many incorrect determinations of occipitana. The genitalic structure depicted in that photograph is now associated with Pelochrista Lederer, which no doubt explains the current placement (Powell 1983) of occipitana in that genus. The purposes of this paper are to illustrate the species to which the name occipitana properly applies and show that it belongs in Eucosma-. to make available names for two new species of Pelochrista previously misinteipreted as occipitana-, to review the current Nearctic members of Pelochrista that appear to be most closely related to these new taxa, based on male genitalia; and to descrilie two additional new species of Pelochrista that have affinities with members of this group.

The taxon illustrated by Heinrich (1923) as occipitana is described below as Pelochrista ainsliei. new species. It is one of six Nearctic species of Encosmini in which the v'alva has, in addition to several spiniform setae at the

anal angle of the cuculhis, a particularly large spine projecting from the ventral margin of the neck. A second such taxon, also inisidentified in collections as occipitana, is described below as Pelochrista kingi, new species. The remaining members of the group are: Eucosma mediostriata (Walsingham), which is transferred here to Pelochrista, Pelochrista reversana (Kearfott), Pelochrista palpana (Walsingham), and a third new species described below as Pelochrista gilligani.

In assembling specimens for this study I encountered a previously unrecognized species from California that is superficially similar to some pheuotyjres of mediostriata but resembles Pelochrista fuscosparsa (Walsingham) in genitalic structure. It is described below as Pelochrista fuscostriata, new species, and an account of fuscosparsa is included.

Eucosma biquadrana (Walsingham) is another western taxon that has not been correctly identified in North American collections. Heinrich (1923) placed it close to Eucosma palousana (Kearfott) but was unable to compare male genitalia of the two species for lack of authoritatively determined specimens oibiquadrana. In that same monograph, Heinrich described Eucosma tahoensis, based on three specimens that I judge to be biquadrana, and since then biquadrana material in North American collections has been referred consistently to tahoensis. I examined the types of biquadrana, palousana. and tahoensis and concluded that they represent a single taxon. Although the last two species are currently placed in Pelochrista (Powell 1983), I propose that biquadrana remain in Eucosma (until the distinction between the two genera can be

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clarified) and that paJousana and tahoensis be treated as junior sNaionyms. A brief account o{ Eucosma shastana (Walsingham), a little known species from California that is remarkably similar to bicjiiadraua in forewing appearance, is included for comparison.

Materials and Methods

Tbe conclusions in this paper are based on an examination of 475 adult specimens and 116 associated genitalia preparations f rom the following institutional and private collections: American Museum of Natural History, New York (AMNH); Charles D. Bird, Erskine, Alberta (CDB); George J. Balogb, Portage, Michigan; Canadian National Collection, Ottawa, Ontario (CNC); Colorado State University, Fort Collins, Colorado (CSU); BMNH; Essig Museum of Entomology, UC Berkeley (EME); Todd M. Gilligan, Loveland, Colorado (TMG); Edward C. Knudson, Houston, Texas; Los Angeles County Museum of Natural Histoiy, Los Angeles (LACM), Greg R. Pohl, Edmonton, Alberta; Strickland Museum, University of Alberta, Edmonton (UASM); USNM, and Donald J. Wright (DJW). Forewing length (FWL), defined as distance from base to apex (including fringe), is presented as an indication of specimen size. It was measured to the nearest one tenth of a millimeter with a reticule mounted in a Leica MZ9.5 stereomicroseope. Aspect ratio (AR), calculated as FWL divided by medial forewing width, is used as a cnide measure of forewing geometry and is reported as the average, rounded to two decimal places, of a few such calculations. The number of obseiA/ations supporting a particular statistic is indicated by n. The line drawings were made with the aid of a Ken-A-Vision Alicroprojector (Model XIOOO-I). Adult images were edited in Adobe Photoshop CS. Some figures were flipped horizontally, so what appears in an illustration to be a right forewing or valva is in fact the left such item on the specimen. Moiphological terminology follows Gilligan ft fl/. (2008).

Genitalia were mounted on slides for examination under a compound microscope. When obseived in situ, by brushing scales from the posterior end of the abdomen, the large ventral spine on the valval neck of male specimens in the mediosthata group projects medially and is oriented roughly peipendicular to the surface of the valva. However, on slide mounts it was intentionally flattened as much as possible into the plane of the valva to show the size and shape of both the spine and the bulge on the ventral margin of the neck that supports it. Nevertheless, in some of the illustrations the spines appear somewhat foreshortened, depending on the angle of inclination beRveen the spine and the surface of the slide.

In the I950’s, Obraztsov examined the synty^res of mediostriata, fuscosparsa, palpana, hiquadrana, and shastana and selected a lectotyjoe for each species, but his designations were never published. For the sake of nomenclatorial stability. Eve included those designations here. I examined the specimens and associated genitalia slides ol palpana , hi(piadrana, and shastana. For mediostriata and ///.s'ro.s/;r/r.sr/, I relied on 35 nun color slides of the adults and black and white photographs of the ge7iitalia made by Obraztsov.

Species Accounts

Eucosma occipitana (Zeller), revised eombination (Figs. 7, 8, 34, 37)

Paedisca occipitana Zeller 1875: 315.

Eucosma occipitana: Fernald [1903]: 456; Barnes and McDunnough f917: 169; Heinrich 1923: 111; Mc- Dunnough 1939: 47.

Pelochrista occipitana: Powell 1983: 35; Brown 2005: 480.

Diseussion. The image of tlie holot)q?e (Fig. 8) was provided by K. Tuck at tlie BMNH; that of its genitalia (Fig. 37) was obtained from a black and white negative made by Obraztsov of the slide he had prepared. Specimens other than the holotype tliat I located in institutional collections under the name occipitana all proved to be P. ainsUei or P. kingi (both described below). The specimen illustrated in Figure 7 is a male from Pawnee National Grassland, Weld Co., Colorado that I collected on 8 August 2004. Its forewing appearance is not an exact match to the holoty^re, but I have tentatively determined it as occipitana based on similarity of genitalia (Figs. 34, 37). The apparent differences in color could be a consequence of specimen age anchor photographic technicjue, and the more strongly mottled forewing appearance of the holotyjre might easily be attributed to variation. Of course, these issues cannot be resolved without additional mateiial. In color, size, and forewing appearance, occipitana is similar to one of the phenotyjDes (Fig. 6) oi Pelochrista ainsUei Wiight and to Eucosma kandaua Kearfott (Wright 2007, Fig. 12), but the three species are easily distinguished on the basis of male genitalia (Figs. 37, 26, & Wright 2007, Fig. 29). The shape and spining of the valva, together with the presence of a foi'ewing costal fold, suggest that generic placement in Eucosma is appropriate.

Type. Holotyjre: d, Bosque Co., Te.xas, 24 June 1871, Bel- trage, genitalia slide .57.56, BMNH,

Descriptive notes. The dorsal surface of the forewing (Figs, 7, 8) is yellow brown to brown and somewhat mottled in ap- pearance. There are no well defined lascial markings, and the ocellus is veiy weakly e.xpressed. The specimen from Colorado has a FWL of 6.6 mm, with AR = 3..30.

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Figs. 1-24. 1 — 1, P. medioatriata . 1, <S Albany Co., Wyoming. 2, 6 Larimer Co., Colorado. 3, 6 Sanpete Co., Utah. 4, 6 Oneida Co., Idaho. 5-6, P. ainsliei. 5, d Morgan Co., Colorado. 6, d Otero Co., Colorado. 7-8, E. occipitana. 7, d Weld Co., Colorado. 8, holo- Lpe, Te.xas. 9-11, P. kingi. 9, holoLpe, Saskatoon, Saskatchewan. 10, d Albany Co., Myoming, 11, d Nordegg, Alberta. 12, Pe- locliri.sta sp., d Sanpete Co., Utah. 13-14, P rcversana, d, d Kimble Co., Te.xas. 15, P. palpana, lectotvpe, Sliasta Co., California. 16, P gilUgant holoHpe, Sanpete Co., Utah. 17-20, P fusco.sparsa. 1 7, d Oneida Co., Idaho. 18, 19, 20, d, d, d Albany Co., Wyoming. 21—22, E. buiiiii(hriiia. 21, leetoHpe, Shasta Co., California. 22, d. Grant Co., Oregon. 23, E. sitastana. lectoHpe, Siskiyou Co., Cal- ifornia. 24, P fiiscostriata, lioloUpe, San Mateo Co., California.

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Figs. 25-28. Male genitalia. 25, P. mediostriota, slides l)|W1863. 383, 966. 26, F. aiuslici, slides DJW1859, 1344, 148. 27, F khioi, .slides DJW1855, 1671, 1065. 28, F reversana, slides D'|\\4908, USNM70623, USNM70623. Scale bar = 0.5 inin.

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Figs. 29-34. Male genitalia. 29, P. palpaiui, slides DJW1924, USNM70633, DJW11.58. 30, P. gilligani, slides DJ\V1911, 1912, 1912. 31, P. ftiscosparsa, slide 14JW1869. 32, P. fiiscostriata. slide DJW1970. 33, E. hkjuadrana , (paloiisana lectotype), slide CH 20 April 1921. 34, E. occipitana . slide DJW 1138. Scale bar = 0..5 mm.

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Figs. 35-40. Male genitalia. 35, Puedisca mediant riatu, lectotvpe. 36, Paedisca pulpana. lectotvpe, 37, Puedisca occipitana, liolf)- tvpe. 38, Paedisca fuscosparsa, lectotyj^e. 39, Paedisca J)upiadrana. lectotv[ie. 40, Paedisca shastana, lectot\pe.

Male aciiif alia (Figs. .34, .37): Uncu.s aroniKled, dor.sally seto.se lobe; dorsolateral shoidders of tegunien well developed and I lunched; socii long, moderately setose and tapering distally; vesica with 6 (based on the one Colorado specimen) decidnons cornnti; \ alva with weakly concave costal margin, rounded apex, roughiv right-angled anal angle, and moderately emarginated ventral margin; cncnllns with 8—10 long spinilorm setae evenly distributed along distal margin, the longest located near tlie anal angle; medial surface of cncnllns densely covered with stout se- tae. Female genitalia: Unknown.

Pehclmsta iturliosiiiata (Walsingham), new combination (Figs. 1-4, 2,5, 35, 41, 50)

Paedisca mediostriata Walsingham 1895: 508.

Eiicosma mediostriata: Fernald [1903]: 460; Barnes and McDnnnongh 1917: 171; Heinrich 1923: 116, Fig. 245; McDnnnongh 1939: 47; Powell 1983: 34; Brown 2005: 323.

Eucosma sepuk-rana Meyrick 1927: 334.

Eiicosma scpulchrana: Clarke 1958: 420. [misspelling of sepidcraiia].

Discussion. To make the comparison with E. sepidcraiia Meyrick, Clarke (1958) dissected the specimen designated above as lectop'^^e for mediostriata, hut to my knowledge this choice of name hearing specimen for mediostriata has not been published previously.

The genitalia of the lectotyj^re (Fig. 35) have a large spine on the ventral margin of the valval neck, whicli is

the reason for the proposed reassignment of this species to PeJochrista . Heinrich’s illustration of mediostriata (1923, Fig. 245) shows no indication of the spine on either valva, hut an examination of the associated slide revealed that hotli .spines had been broken off at the socket and apparently lost.

Types. Paedisca mediostriata . Lectotype here designated: d, [Larimer Co.], Loveland, Colorado, ,5()00 It., July 1891, Sinitli, genitalia slide 1FGC6.388, Wlsm. No. .31141, BMNH. Paralecto- tvpes: Loveland, Colorado, (nly 1891; 1 d, ,5-10, ()()() ft, W’Lsni. No. .31119; 1 d, 10,000 ft., wlsm. No. 31 1 18; 1 d, ,5000 ft., Wlsm. No. .31192; 1 d [no elevation indicated], Wlsm. No. 30429; all in tlie BMNH. Encosma sepnlcrana. Lectotvpe designated by Clarke (19.58): d, [Tooele Co.], Dividend, Utah, 26 June, geni- talia slide JFCC6.386, BMNH. Paralectotvpes: 11 specimens [according to Meyrick (1927) and Clark (19.58)], same data as lectotvpe, BMNH.

Descriptiv'e notes. Tlie specific name derives Irom the pres- ence in most individuals of a prominent pale forevvlng streak running anterior to the cubitus from base to distal end of cell (Fig. 2). Often tliin streaks of the same pale color are present along the costa, the median branches, CnA2, ami A1+A2. The streaking is variable and, in some instances (Fig. 1), barely dis- cernable. Forewing color is also variable, from yellowish browm (Fig. 1) to whitish gray (Fig. 4), with numerous intermediate combinations of yellow brown, olive Irnmn, whitish gray, ami lilackish gray. There are no discernalde fascial markings, and the ocellus is not expressed. The hindwlng is black to blackish gray, with Iringe vaiying from wliite to pale gray. Forevvlng statistics: d F-WL: 6.7-12.4 mrn (mean = 10. 1 , n = 71 ), AR = 3..35; 9 FWL: 8.1-1 1.8 (mean = 9.8, n = 14), AR = 3.21.

Male genitalia (Figs. 2.5, 3.5): Uncus semitriangular witli rounded apex; socii fingerlike ami moderately setose; vesica with 18 — 12 deciduous cornnti (n = 1.3); valva with raised clasperlike

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process on margin of basal excavation and with large spine on \entral margin at distal end of neck; cncnilns semirectangular, wdth 3 or 4 spiniform setae at anal angle. Figure 2.5 illustrates the \ ariation in \'alval shape and in the spining of the ventral margin of the cncullus. Female genitalia (Fig. 41): Papillae anales later- ally facing and sparsely setose; lamella antevaginalis ringlike; lamella postvaginalis well developed and semirectangular, with variably wrinkled lateral margins and a sliallow medial trongli from center of posterior margin to ostium; posterior margin of sternum 7 with weakly developed, con\’ex, medial bulge; ductus bursae with small sclerotized patch at juncture watli ductus sem- inalis; corpus bursae with one small signurn.

Distribution and biology. Figure 50 shows tlte geograpliic distribution of mediostiiatcF based tlie 165 specimens (151 d; 14 9) in the study sample. Capture dates range from mid-April (in Texas) to early August, but the vast majority of the records are from June and July. No lannl host has been reported.

Pelochrista ainsUei, new species

(Figs. 5, 6, 26, 43, 50)

Eitcosma occipitana: (not Zeller 1875) Heinrich 1923: 111, Fig. 226; McDunnough 1939: 47.

Pelochrista occipitana: (not Zeller 1875) Powell 1983: 35; Browai 2005: 480.

Diagnosis. This species is separated from other western Eucosmiui of similar torewang pattern and coloration by features of the genitalia. Males are distinguished by the following combination of characters (Fig. 26): uncus moderately developed and not medially divided; ventral margin of vah al neck not emarginated but with strongly developed projection supporting one particularly stout spine; and cncnilns either rounded or with broadly rounded apex and anal angle, the latter with three or more spiniform setae. Distinctive female genitalic characters include (Fig. 43): diamond shaped lateral projections of lamella posF'aginalis; medial projection of posterior margin of sternum 7 fused with sterigma; posterior one-fourth of coipus bursae sclerotized on dorsal and lateral surfaces; and corpus bursae v4th two signa. In size, color, and general appearance, the ainsliei phenotype with weakly e.xpressed forewnng markings (Fig. 6) is quite similar to E. occipitana (Fig. 7) and E. kandana Kearfott (Wright 2007, Fig. 12), but the three taxa have veiy different valvae (Figs. 26, 34 & Wright 2007, Fig. 29). Based on forewing pattern, well-marked specimens of ainsliei (Fig. 5) might be confused \\4th Pelochrista eniaciatana (Walsingham) (Wright 2005, Fig. 10). Moreover, females of these two species have rather similar sclerotized plates on the surface of the coiqyus bursae (Fig. 43, Wright 2005, Fig. 24). However, emaciatana is larger (mean FWL = 10.5 mm \'s. 7.8 mm in ainsliei), it differs from ainsliei in the shapes of the cucullus and valval neck (Wright 2005, Fig. 17 vs. Fig. 26), and it has

only one signurn in the coipus bursae. The apical area of the forewdng in ainsliei lacks the reddish-brown suffusion that is prominent in many specimens of kingi. Genitalic differences betyy^een ainsliei and kingi are discussed below under the latter species.

Description. Head: Frons white to pale tan, scales of vertex pcife tan with white apices; labial palpi watii medial surfaces white, lateral surfaces pale brown; antenna pale tan. Thorax: lOorsal sur- face concolorous with head; ventral surface whitish tan; legs pale brown, with whitish-tan tarsal annulations, Foreicing (Figs. 5, 6): 6 FYt’L 6.4-S.4 inin (mean = 7.7, n = 17), AR = 3.38; 9 FWL 7.7-S.5 mm (mean = 8.1, n = 4), AR = 3.26; costa straight, apex acute, ter- inen weakly convex; dorsal surface Irrowm to yellowish brown, vatli \ ariably expressed darker browm marl-dngs as follows: subbasal fas- cia an outwai'dly oblique bar from dorsum to radius, usually inter- rupted on A1-I-A2, median fascia consisting of a narrow dash at mid costa and an irregularly shaped blotch at distal end of cell, pretor- nal patcli triangular ami projecting anteriorly from dorsum along basal margin of ocellus; ocellus with pale tan central field, crossed longitudinally by up to three dark dashes, bordered basally and dis- tally liy transverse bars ol lustrous pale-tan and/or silvery-white sc;Jes: a longitncUiicil patch of white-tipped brown scrfes anterior to ocellus extends basafly nearly to the subbasal fascia, chrfding the median fascia on the radius. Iliiuhving: Gray brown with paler fringe. Male genitalia (Fig. 26): Uncus a semitriangular. dorsally se- tose lobe; socins moderately setose, broad at base, tapering to nar- rowly rounded apex; gnathos bandlike; aedeagus long, tapering dis- tally; vesica without cornuti; wilva with costal margin weakly concave, cucullus weakK- differentiated, and ventral margin of neck with strongly developed projection supporting a large spine- hke seta; cucullus with apex and anal angle rounded, tlie latter with tliree or four spiniform setae; medial surface of cncullus covered with stout setae. Female genitalia (Fig. 4.3); papillae anales laterally facing, with long ventrally earning setae along lateral margins and larok-tipped setae along medial margins; lamella postvaginalis with diamond-shaped lateral extensions and a shallow, microspinulate, medial trough from YLshaped indentation of posterior margin to ostium; posterior extremities of sterigma and membrane between sterigma and ventral e.xtremities of tergum 8 with numerous, long, hairlike setae; posterior margin of sternum 7 with medial tiiangi.i- lar projection that fuses witli lamella antevaginalis and shields os- tium bursae; coipus bursae with large sclerotized plate at junction witl i ductus bursae, e.xtending over dorsal and lateral surfaces but not closing ventrally; one small signurn located at center of imterior margin of sclerotized patch, a second large signurn on ventral sur- face of bursa.

Holotype. d. New Me.xico, [Dona Ana Co.], Mesilla, C. N. .Ainslie, genitalia slide USNM 70620, USN.VI.

Paratypes. COLORADO: Larimer Co., Fort Collins, 15 June 1920 (1 d), AMNH, 16 June 1920 (1 d), CSU; no locality data (1 d, genitalia slide LISNM 70621), USNM; [Arapahoe Co.], Platte Can[y]on, Oslar (1 d, genitalia slide USNM 70622), USNM: Morgan Co., 3.5 mi. W. of Co. Rd. 19 on Co. Rd. I, 4610 ft, D. J. Wright, 28 July 1995 (1 d, genitalia slide DJAV 148), DJW; Otero Co., Vogel Cyai. Picnic Area, 15 mi. S. of La Junta, 4340 ft, D. J. Wright, 18 August 1997 (1 d), DJW; Otero Co., Comanche NG [National Grassland], 15 mi. S. oi^ La Junta, D. J. Wright, 27 Au- gust 2000 (2 d), DJW; Weld Co., Pawnee Site, L.T.E.R. USDA, P. A. Opler, 27 July 1991 (2 d), CSU; 0.25 mi. N. 1-76 on CR 91, T. M. Gilligan & P. A. Opler, 17 August 2007 (1 9, genitalia slide DJAV 1909k TMG; Pawnee NG. Jcl CR-96 & CR-61, 5030 ft., T. M. Gilligan & P. A. Opler, 31 August 2007 (1 d, genitalia slide DJA'V 2039; 1 9, genitalia slide DJXV 2038), TMG. NEW MEX- ICO: Same data as holotyqje (2 d, 2 9; 9 genitalia slides DJW 1860, 1984, LTSNM; 1 d, genitalia slide DJW 1344, AVINH; 1 d, LACM). MWOMING: [Weston Co.], 6 mi. NW Newcastle, R. W'. Hodges, 23 June 1965 (1 d, genitalia slide DJW 1859), USNM."

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Figs. 41 — 15. Female genitalia. 41, 6 ineiliosiriaUi , slide D|W18fi2. 42, /’ reversami , .slides IISNM9.5247, D)^^'1926, USNM90.5()6, Dj\V1925. 43, R aimJici. slide DJW'lSflO. 44, P. kingi, slide DjrVMS56. 45. P palpaua, DJW' 771. Scale bar = 0.5 mm.

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Journal of the Lepidopterists' Society

Figs. 46—49. Female genitalia. 46, P. fuscosparsa, slide DJW1S71. 47, P. fuscostriata, slide Df\V1971. 48, E. hiqiiadrana, slide DJ4V1596. 49, E. shastana, slide DJW1973. Seale bar = 0.5 mm.

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Etymology. Thi.s .species is named in lionor of Charles N. Ainslie, a cereal entomologist who worked for the Federal Bureau of Entomology fiom 1906 to 1930 (Walton & Caffrey 1940). Mis specimens oi'aiiisliei from Mesilla, New Mexico seem to he tlie first collected examples. Though the pin labels do not indicate date of capture, it is likely these specimens were collected in 1908, when Ainslie was on assignment to New Me.xico to study a population peak of Hcnnileuca olivine Cockerell (Satnrniidae).

Distribution and biology. The t\qie series consists of 21 adults (17 d, 4 9) from Colorado, New Mexico and Wyoming (Fig. 50). Capture dates, which are available for only 13 of the specimens, range from 15 |nne to 31 August. No lamil host is known.

Remarks. The holotype of ainsliei is the specimen illustrated by Heinricli (1923, Fig. 226) as occipitana. The shape of the ciicnllns is variable, as indicated in Fig. 26. All specimens have the large spine on the ventral margin of the neck and a chrster of three or four smaller spines near the anal angle of the cncnilus, hut in some individuals (Fig. 26h) one spine seems to he displaced to midway between these positions. In a given specimen, this condition may he present on one valva and absent on the other.

Petochrista kingi, new species

(Figs. 9-11,27, 44,50)

Diagnosis. This species often can he distinguished from congeners with similar forewing markings by the presence of at least some reddish-brown suff usion in the apical portion of the forewdng. The male genitalia (Fig. 27) are similar to those of ainsliei (Fig. 26), hut the uncus is distinctly divided medially, the socii are narrower, the support for the large spine on the ventral margin of the neck is less strongly developed, the cucnilus is semirectangular, and the anal angle of the cucullus usually has only two spiniform setae. Females (Fig. 44) are characterized by the ringlike lamella antevaginalis, the nearly complete sclerotization of the ductus bursae, and the presence of only one signum in the coipus bursae.

Description. Head: Frons and vertex white to pale tan, \’er- tex scales sf)inetimes marked medially with pale grarish brown; labial palpi with medial snriaees white, lateral surfaces pale gray- ish browm; antenna concolorous \rith vertex. Thorax: Dorsal sur- lace concolorous with head but often a shaile darker, ventral sur- face pale whitish tan; legs brown with whitish tarsal annulations. Foreu'ing (Figs. 9-11): d FVVL 7.9-10.0 mm (mean = 8.9, n = 2.5), AH = .3,14; 9 PA\'L S.0-8.9 mm (mean = 8.4, n = 7), AH = 3.04; costa and termen weakly convex, apex acute; dorsal surface tan to grayish brown with brown to blackish-brown markings; termen and distal one half of costa with reddish-browai snffn- sion; snlrbasal and median fasciae variably e.xpressed, the former an outwardly oblicjiie bar from dorsum to radius tliat is often in- terrupted on A1 + A2, the latter an irregularly shaped mark at dis-

tal end of cell that is connected to the costa by a liareK discern- able brownish streak; pretornal patch irregular in shape and ex- teiuling anteriorly from dorsum along basal margin of ocellus; costal lold darker than adjacent interfascial scaling; ocellus v\ith brow'uish central field crossed longitudinally by up to four dark dashes and bordered basally and distallv l)y lustrous gray trans- verse bars; apex and termen lined with about five rows of scales with bright white apices and sliaiply contrasting, dark, grayish- browm, medial markings. 1 1 hidwiu^: Pale grayish browm. Male genitalia (Fig. 27): Uncus weakly developed and divided medi- ally: tlorsolateral shonklers of tegumen linnched; socii long, nar- nnving distally, and moderately setose; gnathos bandlike; aedea- gus long and narrow; vesica w'itliont cornnti; valva with costal and ventral margins nearly parallel and with a weakly developed projection on ventral margin at mid neck supporting a large spiniform seta; cncnilus semirectangular; apex obtuse to righ- tangled; anal angle often narrowK' rounded but wath moderately developed ventral projection in some individuals (Fig. 27b), in either case supporting two large spiniform setae; meilial surface of cucullus covered with stout setae. Female genitalia (Fig. 44): f^apillae anales laterally facing, lateral margins with long ven- trally enning setae, medial margins sinuate and linerl w'ith hook- tipped setae; sterigma ringlike anteriorly; lamella postvaginalis a shieldlike plate with a shallow central trough joining ostium to medial indentation in posterioi' margin; posterior margin of ster- num 7 bulging ventrally and weakly shielding ostium; sclerotiza- tion ol sternum 7 more strongly pronounced along posterior and lateral margins, ductus bursae almost entirely sclerotized, but witli a narrow membranous ring between juncture w'itli ductus seminalis and coipus bursae and w'ith a narrow membranous strip on ventral surface from ring to corpus bursae, anteiior compoueiit of sclerotization projecting laterally