Lycaena phlaeas
American Copper

Family Description:
Alternate Common Names:
Flame Copper, Small Copper.

The caterpillar varies in color. It can be either reddish with yellow shading on the sides, or light to yellowish green and possibly marked with red on the back or sides. The body is covered with downy hair. It reaches an average, full-grown length of 3/4 inch.
Adult: This is a fairly small to medium-sized butterfly, with a wingspan of 7/8 to 1 3/8 inches. Its upperside is two-toned: the forewing is orangish red, spotted with dark brown, and edged with a wide brown band. The hindwing is brown to gray with a orangish red band just in from the outer bottom edge. Underneath, the forewing is orange, spotted with black, and edged with gray. The underside of the hindwing is grayish white, dotted with black, and marked with a thin, curved, jagged orange line just in from the edge.

Primarily an introduced eastern species, it ranges from Nova Scotia south to Georgia, and east to Minnesota and the Dakotas south to Arkansas. It also occurs as a native in patches of arctic Canada, in northern Alaska south and west to British Columbia and Alberta, and in patches of the Rockies. It has been documented in Idaho in Lemhi County.


In the east it can be found in open or disturbed areas, including pastures, fields, and landfills; in the west it occurs in rocky alpine places or arctic tundra.


Caterpillar: In the east, caterpillars feed on the leaves of sheep sorrel (Rumex acetosella) and curly dock (R. crispus); in the west, caterpillars feed primarily on mountain sorrel (Oxyria digyna).
Adult: Butterflies drink flower nectar.


The number of generations of caterpillars each summer depends on the location, with three or four in the south, two in the north, and one in alpine and arctic areas. Each caterpillar undergoes four to five stages of growth, called instars. Either caterpillars or pupae overwinter in a physiological state called diapause. Adults generally fly from May through September in most of its range, and from July through August in the western and arctic parts of its range. These butterflies have been known to be aggressive, chasing almost anything passing by.


Males perch to wait for receptive females. Females lay ribbed, pale green eggs singly on the leaves or stems of host plants.

Idaho Status: Unprotected nongame species.
Global Rank: G5; populations are widespread, abundant, and secure.

Ballmer, G. R. and G. F. Pratt. 1988. A survey of the last instar larvae of the Lycaenidae of California. Journal of Research on the Lepidoptera 27:1-81.

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.