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Vol.11: nos.1-3
NOTES ON ATRYTONE DUKESII, A RARE SPECIES NEW TO SOUTHERN MICHIGAN (HESPERIIDiE)
by Thomas E. Pliske
Atrytone dukesii Lindsey is an intensely local skipper which inhabits shaded swamps. Before the discovery of the Michigan locality, dukesii was known from only three other colonies which are North Landing Swamp, Va., Payne, Ohio, and Mobile, Ala. The nearest of these other locations, that in Ohio, is approximately 100 miles S.S.E. of the Michigan colony.
Atrytone dukesii was discovered in Michigan for the first time on July 21, 1956, in Washtenaw Co. by Arthur Slater and T. E. Pliske. Slater and Pliske took two males in a small fresh water marsh on the north side of the Huron River, about 1 miles east of Ann Arbor. On the following day, July 22, an expedition consisting of T. H. Hubbell, W. H. Wagner, S. P. Hubbell, Slater, and Pliske was made to the locality. The weather was cloudy and a storm was threatening; however, one male was taken and later placed in the University of Michigan collection. Five days later, on July 27, a second locality was discovered half a mile east of the first. There a female was taken and a male was observed, and on the next day, two more females were seen at the second locality.
The following year, 1957, on July 13, a female was taken at the first locality, and on July 15, a male was taken at the second locality.
Both marshes in which Atrytone dukesii was taken were dominated by the sedge, Carex laeustris Willdenow, or "Lake-margin sedge." The C. laeus-tris association seems to be quite common as was seen from field trips made in Washtenaw, Lenawee, and Jackson Counties on July 29. Carex laeustris is easily recognizable because of its broad blades (usually a centimeter or more), and the criss-cross manner in which they spread.
We, therefore, have definite reason to believe that C. laeustris is the food plant of A. dukesii due to the fact that all dukesii specimens were taken in marshes where C. laeustris was predominant. Further evidence which lends credence to our suspicions was discovered on July 28, when Wagner, S. Hubbell, and David Ackley observed a female ovispositing on the suspected sedge. The eggs were laid on the underside of the leaves, about one and one-half feet off the ground. When the collectors left the field, Wagner took several of the eggs and some sedge with him. The female was not taken but was unquestionably A. dukesii.
The eggs were drawn under camera lucida. When first secured, the eggs had a pale pea-green color, but after 24 hours the egg; which developed the furthest formed two reddish rings, one on the anal portion, the other medial. None of the eggs actually hatched, but one developed to a stage where one could see the tiny caterpillar through the transparent eggshell.
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