Euphydryas chalcedona
Variable Checkerspot

Family Description:
Alternate Common Names:
Western Checkerspot, Colon Checkerspot.
Note: This species is comprised of many subspecies, including anicia and colon; however, the subspecies are all variable and difficult to distinguish, and the delineations between them are debated. Some authors consider several of them to be independent species. Additionally, some authors refer to this species with the genus name Occidryas.
Caterpillar: The caterpillar varies in appearance, but generally is black marked with white, yellow, or orange. The body is covered with hair, and there are black and orange spines.
Adult: This butterfly is small to medium-sized, with a wingspan of 1 1/8 to 2 1/4 inches. Like the caterpillar, the butterfly is variable in appearance. Typically, the upperside is black to dark brown. The forewing is quite pointed and is marked with whitish to yellow and orange spots with the outer edge lined with red spots. The hindwing is marked mainly with whitish to yellow spots, with the outer edge lined with a row of small yellow dots spaced evenly apart. Underneath is reddish to orange and marked with yellow bands. The sides of the abdomen are often spotted with white.

This species ranges from parts of Alaska and western Canada south through California, through the Pacific Northwest east to the Dakotas, and through the Rocky Mountain and southwestern states. It occurs throughout Idaho.

It occupies a variety of open habitats, including tundra, open forests, chaparral, sagebrush steppe, and desert.


Caterpillar: Caterpillars feed on the leaves, flowers, and bracts of a number of host plants representing several families, including the honeysuckle family (Caprifoliaceae) and the snapdragon family (Scrophulariaceae). Species include snowberry (Symphoricarpos spp.), Indian paintbrush (Castilleja spp.), and beardtongue (Penstemon spp.).
Adult: Butterflies drink flower nectar.

Caterpillars build nests of white silk in which they feed together. There is only one new generation of caterpillars each year in most of the range, but there may be several in the southwest. Caterpillars overwinter in leaf litter or under rocks in a physiological state called diapause. Those at high elevations may remain in diapause for several years. Adults generally fly from June to August through much of its range.

Males actively patrol in search of receptive females. Females lay yellow eggs in clusters on the underside of host plant leaves. The eggs turn reddish brown before hatching.

Idaho Status: Unprotected nongame species.
Global Rank:

G5; populations are widespread, abundant, and secure.

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.