Russet Skipperling (Piruna pirus [W. H. Edwards])
Wing span: 1 - 1 1/8 inches (2.5 - 2.9 cm).
Identification: Upperside is dark brown; underside is red-brown. Forewing above and below has tiny transparent white spots; hindwing has no markings above or below.
Life history: Adults rest with their wings closed, but bask with hindwings open wide and forewings open to about 45 degrees. To find receptive females, males patrol above low plants in river courses, streams, and moist ravines. Caterpillars live and feed within nests of webbed leaves. Fully-grown caterpillars hibernate.
Flight: One brood from June-July.
Caterpillar hosts: Probably grasses such as bluegrass (Poa).
Adult food: Flower nectar.
Habitat: Moist valley bottoms, forest openings, meadows.
Range: Southeastern Idaho, southern Wyoming, Utah, Colorado, Arizona, and New Mexico.
Conservation: Not usually required.
The Nature Conservancy Global Rank: G4 - Apparently secure globally, though it might be quite rare in parts of its range, especially at the periphery.
Management needs: None reported.
Scott, J. A. 1986. The butterflies of North America. Stanford University Press, Stanford, Calif. 583 pages, 64 color plates. Stanford, R. E. and P. A. Opler. 1993. Atlas of western USA butterflies including adjacent parts of Canada and Mexico. Denver and Fort Collins, CO. Tilden, J. W. 1986. A field guide to western butterflies. Houghton-Mifflin Co., Boston, Mass. 370 pages, 23 color plates.
Author: Jane M. Struttmann
State and Regional References:
Ferris, C.D. and F.M. Brown. 1980. Butterflies of the Rocky Mountain States. University of Oklahoma Press. Norman. Opler, Paul A. 1999. Peterson Field Guide to Western Butterflies, revised edition. Houghton Mifflin Co., Boston, Mass. Stanford, R.E. and P.A. Opler. 1993. Atlas of Western USA Butterflies. Privately published, Denver, Colo. Tilden, J.W. and A.C. Smith. 1986. A Field Guide to Western Butterflies. Houghton Mifflin Co., Boston, Mass.