Rhesus Skipper (Polites rhesus [W. H. Edwards])
Wing span: 1 - 1 1/4 inches (2.5 - 3.2 cm).
Identification: Fringes are white. Upperside is dark brown; male stigma is not apparent. Forewing spots are white; larger in the female. Underside of hindwing is greenish brown with white veins, a white band, and irregular dark spots.
Life history: To await receptive females, males perch on small mesas up to 6 feet high or on flats where there are no mesas. Females lay eggs singly on the host plants.
Flight: One brood from May-June.
Caterpillar hosts: Blue grama grass (Bouteloua gracilis).
Adult food: Nectar from flowers including Drummond's milkvetch (Astragalus drummondii).
Habitat: Native short-grass and mixed-grass prairie.
Range: Southern Manitoba south through the grasslands of Montana, Wyoming, the Dakotas, Colorado, Nebraska, Kansas, Arizona, and New Mexico into northern Mexico.
Conservation: Species should be monitored as native short-grass habitats are gradually being replaced by agriculture. Suitable habitats may require moderate grazing.
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:
Brown, F.M., Eff, J.D., and B. Rotger. 1957. Colorado Butterflies. Denver Museum of Natural History, Denver. Ferris, C.D. and F.M. Brown. 1980. Butterflies of the Rocky Mountain States. University of Oklahoma Press. Norman. Layberry, R.A., Hall, P.W. & Lafontaine, D.J., 1998. The Butterflies of Canada. University of Toronto Press, Toronto, ON. 280 pp. 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.