Nymphalis vau-album
Compton Tortoiseshell

Family:Nymphalidae
Family Description:
Alternate Common Name:
Comma Tortoiseshell.
Description:
Caterpillar: The caterpillar is pale green and marked with whitish dots and light stripes; the body and head are covered with black branching spines.
Adult: This is a large butterfly, with a wingspan of 2 to 3 inches. The wing edges are wavy and irregular. The upperside is multi-colored: brownish close to the body, the rest orange to rust colored and marked with large black spots and patches, with the outermost edge golden yellow striped with black. There is a single white spot on both the fore- and hindwing. Underneath is mottled gray, brown, and tan, with the portions closest to the body darker than out toward the wing tips. There may be an irregular, discontinuous line of grayish blue just in from the outside edge. The hindwing has a very small silvery white "V" or comma-shaped mark towards the middle.

Range:
This species ranges from southern Alaska and most of Canada south to Oregon, through the Intermountain and Rocky Mountain states to central Utah and Colorado, through the Dakotas, the Midwest, and the northeastern U.S., extending south as far as Tennessee. In Idaho, it occurs mainly in the panhandle region but also in isolated patches of the southern half of the state.

Habitat:
Its primary habitat is deciduous forests, but it may also utilize coniferous forests and canyonlands.

Diet:

Caterpillar: Caterpillars feed in groups on the leaves of deciduous trees and shrubs including birch (Betula spp.), willow (Salix spp.), aspen and cottonwood (Populus spp.), and elm (Ulmus spp.).
Adult: Butterflies feed on sap, fruit, and sometimes flower nectar.

Ecology:
There is one generation of caterpillars each summer. Adults fly from June until late fall then overwinter, often in groups, in a physiological state called diapause. In spring, they emerge to mate and lay eggs, flying until June. Some adults may migrate to California and Florida. Butterflies may occur in large numbers in a given area one year and few to none may be observed the next.

Reproduction:
It is currently unreported in the scientific literature whether males perch or actively patrol for females; however, males of the other Nymphalis species are reported to perch. Females lay small groups of eggs 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.