Erynnis afranius
Afranius Duskywing

Family:Hesperiidae.
Family Description:
Alternate Common Name: Bald Duskywing


Description:
Caterpillar: The caterpillar is light green, dotted with white, and striped lengthwise with a dark line along the back and yellow on either side. The head is black, also dotted with white, with an orange and black "face."
Adult: This is a small to medium-sized skipper, with a wingspan of 1 to 1 3/8 inches. It is medium to dark brown on the upperside, with the forewing marked with white shading and streaks (males more than females). Males from the season’s spring brood tend to have more white on the forewing than males occurring later in the summer. The hindwing is edged with a pale-tipped fringe of short hairs. Underneath is light to dark brown, with white spots and shading near the outer edges of the wings. Males have a small fold (called a costal fold) on the front inside edge of the forewing, which covers yellow scent scales. 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.

Range:
This species ranges from southern Alberta and Saskatchewan south to Mexico, with an isolated population in southern California. It occurs in isolated patches in Idaho.

Habitat:
It occurs in open areas such as prairies and forest openings and edges.

Diet:
Caterpillar:
Caterpillars feed on the leaves of certain legume species, including lupine (Lupinus spp.), milk vetch (Astragalus spp.), and lotus (Lotus spp.).

Adult: Butterflies drink flower nectar.

Ecology:
Caterpillars live in nests made from leaves rolled or tied together with silk. There are two generations of caterpillars each year in most of the range, and possibly more in the Californian population. The overwintering stage has not been observed or reported. Adults generally fly from March through August.

Reproduction:
Males perch to wait for receptive females. Females lay eggs singly under the leaves of host plants.

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


References:

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. http://www.npwrc.usgs.gov/resource/distr/lepid/bflyusa/bflyusa.htm (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.