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Silvery Blue Glaucopsyche lygdamus


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Silvery Blue
credit: D. Gordon E. Robertson/CCSA

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Family: Lycaenidae, Gossamer-wing Butterflies view all from this family

Description The Silvery Blue (Glaucopsyche lygdamus) is a small butterfly native to North America. Upperside is a light blue in males, a dull grayish blue in females. Underside is gray with single row of round spots of differing sizes depending upon region.

G. lygdamus is found over much of the western United States and most of Canada extending north excepting most of Nunavut and the high Arctic islands. Wingspan is from 18 to 28 mm.

Dimensions Wingspan is from 18 to 28 mm.

Endangered Status The Palos Verdes Blue, a subspecies of the Silvery Blue, is on the U.S. Endangered Species List. It is classified as endangered in California. This butterfly relies on a single plant species, called the Southern California Locoweed. After a critical coastal sage scrub habitat in Palos Verdes Peninsula containing its food plant was turned into a baseball diamond, the butterfly disappeared and was presumed extinct. Eleven years later a population of Palos Verdes Blues was spotted in a small stand of its host locoweed. The butterfly now survives on Department of Defense property. Efforts are being made to save critical habitat and reestablish the locoweed in its native range.

Habitat Alpine & subalpine habitats, Canyons & caves, Forests & woodlands, Freshwater swamps, marshes & bogs, Meadows & fields.

Range Southeast, Northwest, Southwest, Great Lakes, Mid-Atlantic, Rocky Mountains, New England, Plains, Eastern Canada, Western Canada, Alaska, California.