Erynnis persius
Persius Duskywing

Family Description:
Alternate Common Name: Hairy Duskywing.

Caterpillar: The caterpillar is light green, dotted with white, and covered with hairs. It is marked lengthwise with a dark green stripe along the back and a yellowish stripe along the side. The head is red to yellow and marked with white.
Adult: This is a medium-sized skipper, with a wingspan of 1 to 1 5/8 inches. It is light to dark brown on the upperside. The forewing is marked with light dots and hazy streaks. Males have a small fold (called a costal fold) on the front inside edge of the forewing, which covers yellow scent scales, and their forewing is noticeably hairy. Males also possess long "hairs" on the upper sections of the hind legs, called tibial tufts, used to direct pheromones towards a female during courtship. The hindwing of both sexes is lightly marked with rows of hazy black and brown spots. Underneath is similarly marked but paler in color.

This species has a fairly large western range and a smaller range in the east. In the west, it ranges from central Alaska south through the western half of Canada and the northwestern U.S., extending patchily into northern California and the southwest. In the east, it ranges from Wisconsin west to the north Atlantic states, and south to the Appalachian Mountains. It occurs throughout most of Idaho.

It can be found in a variety of open areas, such as grasslands, open woodlands, and sandy plains.

In the east, the caterpillar feeds on the leaves of lupine (Lupinus spp.), and possibly willows (Salix spp.) and poplars (Populus spp.); in the west, hosts are legumes including golden banner (Thermopsis spp.) and lotus (Lotus spp.).
Butterflies drink flower nectar.

Caterpillars live in nests made from leaves rolled or tied with silk. In most of its range, there is one generation of caterpillars each growing season; there may be two or more in California. Older caterpillars overwinter in a physiological state called diapause. Adults fly from April through June.

Males perch to wait for receptive females. Females lay green eggs singly on the undersides of leaves of the host plant. The egg turns pink before hatching.

Idaho Status: Unprotected nongame species.
Global Rank: G5
populations levels are secure, but may be of concern in the future.

Ferris, C. D. and F. M. Brown. (eds.) 1981. Butterflies of the Rocky Mountain States. Univ. of Oklahoma Press, Norman, Oklahoma, USA, 442 pp.

Opler, P. A., H. Pavulaan, and R. E. Stanford. 1995. Butterflies of North America. Jamestown, North Dakota, USA: Northern Prairie Wildlife Research Center Home Page. (Version 05Nov98).

Opler, P. A. and A. B.Wright. 1999. A Field Guide to the Western Butterflies.   Second Edition.  Peterson Field Guide Series. Houghton Mifflin Company, New York, New York, USA, 540 pp.

Pyle, R. M. 1981. National Audubon Society Field Guide to North American Butterflies. Alfred A. Knopf, Inc., New York, New York, USA, 924 pp.

Scott, J. A. 1986. The Butterflies of North America. Stanford University Press, Stanford, California, USA, 583 pp.

Stanford, R. E. and P. A. Opler. 1993. Atlas of Western U.S.A. Butterflies (Including Adjacent Parts of Canada and Mexico). Published by authors, Denver, Colorado, USA, 275 pp.