silvery blue

not listed

N5 - Secure

SNR - Unranked

not listed

Silvery blue is a common, exotic, early season, medium-sized, typical blue butterfly. It occurs throughout the United States and Canada. In the United States it is most common in New England, south along the Appalachian Mountains, and west of the Great Plains. It is mostly absent from the southeast and south-central regions. It is common in Minnesota.

Adults are found from late April to mid-June in a variety of habitats, including prairies, meadows, brushy fields, bogs, woodland openings, sand dunes, and roadsides. They can often be found at damp soil or sand. The caterpillars feed on the flowers, seed pods, and leaves of plants in the Legumes (Fabaceae) family, including alfalfa, bird’s-foot trefoil, crown vetch, locoweeds, lupines, milkvetches, sweet clovers, vetches, and wild peas.

There are currently 20 living (extant) subspecies and one extinct subspecies of silvery blue. All of the extant subspecies occur in North America. Only one species, Couper’s silvery blue, also called northern silvery blue, occurs in Minnesota. Couper’s silvery blue is native to Canada. It was first found in Maine in 1967, and later in New York in 1984. It was first observed in Minnesota in 2008 in Crow Wing County, then not again until 2011 in Rice County. Its range has been rapidly expanding southward thanks to the introduced cow vetch and crown vetch planted along freeway and highway corridors to control erosion.

Adults have a ⅞″ to 1¼″ (22 to 32 mm) wingspan.

The wings of the male are iridescent silvery blue above with narrow but distinct black borders. On the female, the wings are darker, duller, and grayish blue, and they have wider but less distinct black borders. On both sexes, the fringe is white. The underside is gray to brown. The forewings and hindwings have a single row of round black spots rimmed with white.

Wingspan: ⅞″ to 1¼″ (22 to 32 mm)

Eastern tailed-blue (Cupido comyntas) hindwing has a hair-like tail. The forewing has orange caps on 2 or 3 marginal eye spots near the tail.

Spring azure (Celastrina ladon) wing underside is lighter. It has many dark spots that form a wide band, not a single row. There is a row of dark chevrons above dark spots in the terminal area.

A variety of habitats, including prairies, meadows, brushy fields, bogs, woodland openings, sand dunes, and roadsides

One generation per year: Late April to mid-June

Eggs are laid singly on flower buds and young leaves of host plants. Males emerge in May about one week before females.

Pupae overwinter.

Plants in the Pea (Fabaceae) family, including alfalfa, bird’s-foot trefoil, crown vetch, locoweeds, lupines, milkvetches, sweet clovers, vetches, and wild peas

Flower nectar

4, 21, 24, 27, 29, 30, 75, 82, 83.

Common

Location: Uncas Dunes SNA