Chlosyne acastus
Sagebrush Checkerspot

Family Description:
Alternate Common Name:
Acastus Checkerspot.
Note: This is really a complex comprised of several species or subspecies, including C. neumoegeni and possibly others. This species is referred to by the genus name Charidryas by some authors.
Caterpillar: The caterpillar is black, covered with spines, and marked with off-white dots and rows of orange crescent-shaped spots along each side.
Adult: This is a medium-sized butterfly, with a wingspan of 1 to 2 inches. The upperside of the butterfly is checked with orange, yellowish orange, brown, and black; some females may be brownish black with checks of yellow only. The hindwing has three outer rows of orangish checks, the middle of which is the darkest. There is also dark shading where the hindwing attaches to the body. The underside of the forewing is orange marked with black, sometimes with several white checks at the tip and along the edge. The underside of the hindwing is marked with alternating bands of white and orange, divided into checks by black lines.

This species ranges from eastern Washington to eastern North Dakota, and south through eastern California over to northern New Mexico. In Idaho, it has been documented primarily in the southwest and eastern portions of the state.

It is found in dry habitats including sagebrush steppe and pinyon-juniper woodlands.


Caterpillar: Caterpillars eat the leaves and flowers of rabbit brush (Chrysothamnus viscidiflorus) and other members of the sunflower family (Asteraceae).
Adult: Butterflies drink flower nectar.

The caterpillars feed in groups. There may be one to three generations of caterpillars each summer, the last of which overwinters under rocks in a physiological state called diapause. Some caterpillars may remain in diapause for multiple seasons or years before emerging to continue feeding and to pupate. Adults generally fly from February through November.

Males perch to wait for receptive females, or they may actively patrol in search of them. Females lay groups of eggs on the bottomsides of leaves of host plants, and occasionally on flower buds.

Idaho Status: Unprotected nongame species.
Global Rank:

G4; population 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.