310 JOURNAL OF THE LEPIDOPTERISTS' SOCIETY

GENERAL NOTES

ECOLOGICAL NOTES ON CELASTRINA EBENINA (LYCAENIDAE)

Among plebejine blues, Celastrina ebenina Clench is notable for having females that are partly lustrous pale blue above, whereas the males are dull blackish or grayish-brown: the reverse of the usual situation in species with dimorphic sexes. This taxon (for which an appropriate English common name might be "dusky azure") was not recognized as a species until 1972. Its geographical range, however, ex­tends roughly from Indiana to Pennsylvania, south to North Carolina, biologically one of the better known regions in North America. Compared with its close rela­tive, Celastrina pseudargiolus, the new species is rare and local, known from only 13 localities (including several new ones reported below).

We attempted to obtain information on habitat and behavioral differences, if any, between the rare species and the common species. Where C. ebenina occurs, C. pseudargiolus is apparently always present. Wagner visited two C. ebenina localities in the spring of 1975. The first of these was an unreported one discovered by Showalter in Poverty Hollow, Montgomery Co., Virginia. Showalter took a single male there in flight on 23 April 1972, and the following year another single male was taken at the same spot on 15 April. Efforts to rediscover the butterfly in Poverty Hollow during 13-15 April 1975 failed, even though such other butterflies as C. pseudargiolus, Glaucopsyche lygdamus, Pyrgus centaurae, and an unidentified Cal­lophrys were flying. The precise spot where Showalter found his specimens was re­visited many times but without results. The habitat is a dry second-growth area where burning and logging took place a few years ago. Now it is grown up with young pines, brambles, and various acid-soil members of the heath family such as blueberries. It seems possible that the individuals found were casuals, and that the metropolis of the species in Poverty Hollow is elsewhere, perhaps in a more mature hardwood forest area nearby.

On 3-5 May 1975, Wagner went to Clench's locality near Zaleski, Vinton Co., Ohio (Clench 1972, Ann. Carnegie Mus. 44: 33-44) and, following his directions (in litt.), located the exact site. The first two days were cloudy, and only a few butterflies were observed. On the third day the weather cleared, and ca. 20 readily identifiable individuals of C. ebenina of both sexes were seen. Also found in the general vicinity were Pyrgus centaurae, Colias philodice, Vanessa (Cynthia) virgin­iensis, Papilio spp., Strymon melinus, Panthiades m-album, and Callophrys henrici. Skippers of the genus Erynnis ( especially E. iuvenalis) were abundant everywhere along roadsides. Celastrina pseudargiolus was common throughout the area, both in woodlands and along roadsides, where the males were clustered on moist earth.

Celastl'ina ebenina was confined strictly to the tiny valley site described by Clench with only one exception. A solitary male was "mudding" with far more numerous C. pseudal'giolus ca. 14 mile away along a dirt road. Recognition of females in the field is somewhat difficult, but the blue color has a grayish-green cast, and the flight pattern may be different (see below). A few specimens were taken, but most of the butterflies were only observed.

Males are much less conspicuous on the wing than males of C. pseudargiolus be­cause they lack the blue reflectance. We found males of C. ebenina difficult to de­tect and follow in flight except in unusually good circumstances. Both sexes flew lower and faster than C. pseudargio[us. This was observed especially well in the open areas of the habitat. The males tended to have a direct, swift flight within one foot of the ground vegetation, with much "exploring." Celastrina pseudargiolus generally had slower, rather fluttery, more up and down flight, and usually in the upper shrub layer.

No actual instances of C. ebenina feeding on flowers were observed, but several males hovered around Jacob's ladder (Polemonium reptans) flowers and stemless

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blue violets (Viola cf. cucullata). One male landed on the petal of a Cranesbill flower (Geranium maculatum).

Egg-lying was not observed, and thus no information on potential larval foods was obtained. Every plant species we saw both in and out of the small valley was common and widespread. It is possible that foodplants are various and that the limiting factor in local distribution involves something special about the habitat. Certainly the confinement of the Zaleski population to its little valley is extraordinary. We searched in many gulleys and woodlands in the region but found no additional populations, which indicates that other populations, if present, are very scattered.

The Zaleski habitat is difficult to assess botanically because the north-facing slope has a very different flora from the one facing south. The north-facing slope has a maple-basswood association. Such rich woodland forbs as species of Viola, Dicentra, Orchis, and Trillium are prominent. The south-facing slope is much more exposed and dry, and it has an oak-hickory association. Fewer forbs occur at ground level, and there is a strong development of ericads. The center of the C. ebenina habitat is a cool, moist opening, just below a rocky waterfall. Here the dominant plant is spicebush, Lindera benzoin. If C. ebenina originates in the adjacent woods, we are inclined to associate the species with the north-facing slope. We actually saw a few specimens ca. 50' above the bottom of the valley on that slope, and most of the specimens arriving below the waterfall came from that side.

There is some question about how far west C. ebenina occurs. Until recently, the Zaleski site was the farthest west of thoroughly documented localities. Clench (1972) reports the species far to the northwest in Wabash Co., Indiana. In 1972, David K. Parshall (pers. comm.) encountered a small colony in the Fort Hills State Park in Highland Co., Ohio, southeast of Hillsboro. This is over 50 miles to the west of the Zaleski site and is the second record for Ohio. Parshall informed us that the butterfly is "intensely local" and seems to appear "a little later than C. pseudargiolus." His locality, along with the two in Kentucky described below, represent the western extent of C. ebenina based upon actual specimens.

We herewith report C. ebenina for the first time from Kentucky. On 21 April 1974, Gerald B. Straley and Wagner visited a richly wooded area along Rt. 77 in Menifee Co. ca. liz mile north of the Menifee-Powell line, where the following butterflies were flying: Amblysci1tes vialis, Erynnis iuvenalis, E. icelus, Epigyreus clams, Everes comyntas, and Pieris virginiensis . Among the blues collected by Straley, one was later identified as a female C. ebenina.

In Breathitt Co. near Elkatawa, Showalter took a single female C. ebenina on the wing on 26 April 1975. In Menifee Co. near the junction of Rt. 77 and the Powell Co. line, close to where Straley found the species, two males were taken on mud on 27 April 1975.

From the evidence so far, the species appears to be closely associated with more or less mature, rich, deciduous forest. The general impression is that this scarce butterfly is most often encountered singly or in groups of a few individuals. Sizable populations are unusual, as is the case with such other lycaenids in the eastern United States as Erora laeta and Euristrymon ontario. Price (1974 J. Lepid. Soc. 28: 268) found C. ebenina several times in Buncombe Co., North Carolina, but observed only one or two individuals at a time. S. S. Nicolay (in lift.), however, saw the species in considerable numbers during the early 1950s in Pendleton Co., West Virginia.

We should like to recommend that care be taken to preserve the natural popula­tions of C. ebenina. A better pursuit than merely making large collections of them would be to observe the insect and learn more of its habitat, larval food, and adult behavior, especially in comparison with the ever-present C. pseudargiolus, with which it was so long confused.

We wish to acknowledge the help of Harry K. Clench, John Evans, Donald J.

312 JOURNAL OF THE LEPIDOPTERISTS' SOCIETY

Harvey, S. S. Nicolay, David K. Parshall, Gerald B. Straley, and Florence S. Wagner in making this study.

W. H. WAGNER, JR., Department of Botany, The University of Michigan, Ann Arbor, Michigan 48104.

AMOS H. SHOWALTER, Department of Entomology, University of Kentucky, Lex­ington, Kentucky 40506.

A MIGRATION OF VANESSA CARDUI (NYMPHALIDAE)

Recently, in arranging a 25 year collection of Manitoba butterflies, a short series of eight specimens of Vanessa cardui (Linnaeus) was located in the writer's col­lection. Two are dated 4 June 1952; five are dated 5 June 1952 and one is dated 7 June 1952. These are small specimens as compared to locally emerged autumn specimens.

The above eight specimens (a ninth has just been found in the Sam Waller Mu­seum at The Pas from the same series and collection dates) were netted from among dozens that were flying at shoulder height from the east into the northwest. This is against the prevailing winds in this part of Canada.

The migration started on the first of June 1952 and continued for the next seven days. The flight was a light one and the specimens are in remarkably good con­dition. The flight went through the eastern part of the town of four thousand people. One of two butterflies could be seen crossing a town block at anyone time. They would also come in spurts of three or four and then there would be pauses when none would be seen. The flight was most pronounced at about 1600 hours. The butterflies then flew lower and into the setting sun. The flight ended at the end of the week as suddenly as it had started.

Vanessa cardui cannot survive our severe winters this far north in Canada. The autumn generation here is produced from spring migrants. In some years not one V. cardui is seen all summer. Those that are locally produced in August are very large and brilliantly marked.

The migration of 1962 was of continental dimensions and reached The Pas. It was locally abundant and coincided with the blooming of the dandelions in the first week of June. In this regard it resembled the 1952 local flight.

There is, however, a vast difference between specimens of the two flights sep­arated by a lO-year period. In the 1952 flight the specimens were small, well marked and fresh looking. Specimens of the 1962 flight were large, much worn and tattered and were in greater numbers than the 1952 flight. In 1962 almost every dandelion had its butterfly. No directional flight was noted. They suddenly appeared in vast numbers in The Pas area and gradually became more and more tattered. The flight died out naturally here, not moving elsewhere. The local autumn flight is at best a small one in most years. There are not as many thistles around as there were in the 1950's. The use of herbicides along roadsides possibly accounts for this. A day's collecting in the fall produces a few specimens of Vanessa cardui in the best of years.

The 1952 June migration, strangely enough, did not produce a large autumn flight. This was expected and proved a disappOintment when it failed to materialize.

It is probable that the remarkable heat wave, breaking all previous records, on 19 April 1952, influenced insect movements locally. At The Pas the heat persisted for three days, "bringing out" many species of noctuid moths in large numbers. Rare species appeared in numbers that have not been taken since.

The temperature rose to 80°F ... producing a sultry night. This is unheard of in these parts in April. It resembled an August night before a storm! These weather conditions may have initiated the Vanessa cardui migration some weeks later.

WALTER V. KRIVDA, P.O. Box 864, The Pas, Manitoba, Canada.