Cercyonis oetus
Small Wood-Nymph
Family:Satyridae
Family Description:
Alternate Common Names:Least Wood-Nymph, Dark Wood-Nymph.
Description:
Caterpillar: The caterpillar is yellow to light green, with dark green and yellow stripes along the back and a yellow stripe along each side. The head is green, the back end has two red "tails", and the body is covered with fine white hair.
Adult: The butterfly is medium-sized, with a wingspan of 1 1/4 to 1 7/8 inches. The upperside of the forewing is light to dark brown and marked with one eyespot (in males) or two (in females), in which case the top spot is larger and the bottom spot is noticeably closer to the edge. Underneath, both sexes have two eyespots on the forewing, the lower one being smaller and nearer to the edge. The underside of the hindwing is black to mottled brown, marked with irregular brown lines.

Range:
This species ranges from southern British Columbia, Alberta, and Saskatchewan, south through the northwestern quarter of the U.S., and extending further south through northern Arizona and most of New Mexico. It occurs throughout most of Idaho.

Habitat:
 It is commonly found in drier habitats, such as grasslands, sagebrush steppe, chaparral, and pine forests.

Diet:

Caterpillar: Caterpillars feed on grasses (Poaceae).
Adult: Butterflies are known to drink flower nectar from yellow flowers in the sunflower family (Asteraceae) and from the buckwheat family (Polygonaceae).

Ecology:
 There is one generation of caterpillars each summer. The young caterpillars do not feed before overwintering in a physiological state called diapause. In spring, they emerge to feed, molt, and eventually pupate. Adults generally fly from early June to October.

Reproduction:
 Males actively patrol in search of receptive females. Females lay off-white, barrel-shaped eggs singly on host plants.

Conservation:
Idaho Status: Unprotected nongame species.
Global Rank:

G5; populations are widespread, abundant, and secure.

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.