Boisduval's Blue
Plebejus icarioides (Icaricia icarioides)
Common Blue
Description
1-1 3/8" (25-35 mm). Above, male silver-blue to violet-blue, with dark margins, usually without FW cell mark. Female completely brown or with blue restricted to wing bases, with or without FW cell mark. Below, both sexes pale or silver-gray to cream-tan or brownish with
black spots on FW, black or white spots on HW; sometimes marginal crescent row (often very faint) and orange absent or limited to a few rust-colored HW spots usually smaller than FW spots, prominently encircled with or replaced by white. Bar near HW cell below more white than black.
Endangered Status
Two subspecies of the Boisduval's Blue are on the U.S.
Endangered Species List. The Fender’s Blue is classified as endangered in Oregon, and the Mission Blue is classified as endangered in California. Both of these subspecies have suffered as development has eliminated the plant species that they need in order to complete their life cycle.
Similar Species
Silvery Blue has fewer, usually more prominent black spots below. Greenish Blue has HW spots below as large as those on FW and a touch of orange at HW outer angle (tornus).
Life Cycle
Egg delicate green; laid on lupine (over 40 species or forms of Lupinus recorded as host plant, but usually only one used in a given area; always hairier lupine preferred). Caterpillar, to 3/8" (10 mm), green and covered with short white hair, many diagonal marks along sides; overwinters half grown. Chrysalis, to 5/16" (8 mm), green with red-brown on abdomen; adult emerges in a few weeks.
Flight
1 brood; 1 month or more from April in S. California to August in mountains of California and in Rockies.
Habitat
Sea level to over 10,000' (3050 m), including coastal sand dunes, mountains, valleys, meadows, streams, sagelands, and roadsides. Always close to lupines.
Range
British Columbia to S. California, and east to W. Saskatchewan, the Dakotas, Nebraska, W. edge of Colorado plains, and south to E. New Mexico.
Discussion
This highly variable species has over a dozen named subspecies, yet many populations have individuals resembling several varieties.
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