Lycaena [Tharsalea] arota
Tailed Copper

Family Description:
Alternate Common Name: Arota Copper.

Caterpillar: The caterpillar is green and covered with tiny white bumps and short yellowish white hairs. It is marked lengthwise with two white lines along the back and a yellow line along each side. It reaches an average, full-grown length of 3/4 inch.
Adult: This is a fairly small butterfly, with a wingspan of 7/8 to 1 3/8 inches. It has a short, thin tail extending from the rear of each hindwing. Males are reddish brown on the upperside and may have a purplish sheen. Females are brown and marked with golden orange in large patches and bands. Both sexes are marked with orange along the edge of the hindwing, with the orange extending onto the tail. Underneath, the forewing of both sexes is grayish brown clouded with orange and spotted with black; the outer edge is marked with wavy, alternating bands of white and grayish brown. The underside of the hindwing is brownish gray, spotted with black, and marked along the outer edge as on the forewing. The rear of the hindwing is marked with a thin orange line, somewhat shaped like the letter "M" with the center extending onto the tail.

This species occurs in scattered portions of Oregon, California, and Nevada, and from southeastern Idaho south to Arizona and New Mexico, again in scattered patches.

It can be found in open woodlands, mountain meadows, chaparral, and sagebrush steppe.


Caterpillar: Caterpillars feed on the leaves of currant and gooseberry (Ribes spp.).
Adult: Butterflies drink flower nectar, and appear to prefer white and yellow flowers. They can also be observed sipping berry juice and obtaining moisture and salts from mud.

Eggs overwinter and hatch in the spring. There is one generation of caterpillars each year. Each caterpillar undergoes four stages of growth, called instars. Adults generally fly from the end of May through September. Butterflies tend to remain in one location. The thin "tail" on each of the hindwings of adults is thought to mimic insect antennae and thus misleads bird predators into biting at the wrong end and only getting a mouthful of wing, while the butterfly escapes in the other direction.

Males perch to wait for receptive females, and may occasionally patrol. White eggs are laid singly on twigs, dead leaves, or on ground debris near host plants.

Idaho Status: Unprotected nongame species.
Global Rank: Varies with subspecies. Subspecies Lycanea arota nubila of California is ranked as T1, which means it is critically imperiled because of extreme rarity and is imminently vulnerable to extinction.

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.