Euphydryas gillettii
Gillette’s Checkerspot

Family Description:
AlternateCommon Name:
Yellowstone Checkerspot.
Note: This species is referred to with the genus name Hypodryas by some authors.
Caterpillar: The caterpillar is brown to black and marked lengthwise with a yellow stripe along the back and a white stripe along the side. The spines on the back are yellow, while all other spines are black.
Adult: This is a small to medium-sized butterfly, with a wingspan of 1 3/8 to 1 7/8 inches. The upperside is brown and marked with orange and white irregularly-shaped spots. There is a wide orange to red band, bordered on either side by white dots, along the outside edge of the wings. Underneath is similarly marked but paler in color.

This species is restricted to a small range which includes southwestern Alberta, western Montana and Wyoming, and portions of north, central and eastern Idaho.

It can be found in open, moist areas such as meadows, valleys, and open forests.


Caterpillar: Caterpillars feed on the leaves and leaf buds of several species of plants, including twinberry honeysuckle (Lonicera involucrata), snowberry (Symphoricarpos albus), and Indian paintbrush (Castilleja spp.).
Adult: Butterflies drink flower nectar.

Young caterpillars live and feed together in nests made from leaves and silk. There is one new generation of caterpillars each summer. At low elevations, the older caterpillars overwinter in a physiological state called diapause. At high elevations, however, young caterpillars feed for several weeks, then overwinter; in spring, they emerge, feed and molt through the growing season, then overwinter a second time before emerging to pupate. Adults generally fly from late June to mid-August. Butterflies exhibit a slow flight, and tend to stay close to host plants. They roost in the tops of coniferous trees at night, and females may seek shelter there if approached.

Males patrol for receptive females, often in treetops. Females lay eggs in clusters on the undersides of leaves. Investigation revealed that eggs are typically placed on leaves which receive the morning sun because the warmth promotes faster development.

Idaho Status: Unprotected nongame species.
Global Rank:

G3; vulnerable to population decline and extinction.

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.