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Montana Field Guide

Montana Field Guides

Silvery Blue - Glaucopsyche lygdamus

Native Species

Global Rank: G5
State Rank: S5

Agency Status
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General Description
[From Ferris and Brown 1981; Scott 1986; Opler and Wright 1999; Glassberg 2001; Pyle 2002] Forewing 1.3-1.6 cm. Uppersurface of both wings with black margin and white unchecked fringe; male bright iridescent sliver-blue, female dark brown with or without blue basally. Undersurface off-white to gray-brown, forewing with single postmedian row of round and white-edged black spots, hindwing spots as large as on forewing to nearly absent, no marginal or submarginal spots on either wing.

Phenology
One flight; February to mid-May in California, mid-May to mid-July at higher elevation and in the north (Scott 1986). May through June in much of western range, late June through August at high elevation and in Alberta and Saskatchewan, February to April in California (Glassberg 2001). Mid-March to early September in Oregon and Washington (Pyle 2002), late March to mid-August in Oregon (Warren 2005), late April to mid-August in southeastern British Columbia (Threatful 1988).

Diagnostic Characteristics
Best determined by a combination of the uppersurface of both wings with black margin and white unchecked fringe; undersurface off-white to gray-brown, forewing with single postmedian row of round and white-edged black spots, hindwing spots as large as on forewing to nearly absent, no marginal or submarginal spots on either wing.

Species Range
Montana Range

Year-round
 


Range Comments
Alaska south to Baja California and central New Mexico, east across boreal Canada to Quebec, Labrador, Newfoundland, south in the east through the Great Lakes Region and Appalachian Mountains to northern Alabama and Georgia (Scott 1986; Opler and Wright 1999; Glassberg 2001); 1676 m to 3230 m elevation in Colorado (Brown 1957; Scott and Scott 1978; Ferris and Brown 1981), 122 m to at least 2743 m elevation in Oregon (Warren 2005), 456 m to 1829 m elevation in southeastern British Columbia (Threatful 1988). In Montana reported throughout the state (Kohler 1980; Stanford and Opler 1993). Locally uncommon to common (Glassberg 2001).

Observations in Montana Natural Heritage Program Database
Number of Observations: 16

(Click on the following maps and charts to see full sized version) Map Help and Descriptions
Relative Density

Recency

 

(Observations spanning multiple months or years are excluded from time charts)



Migration
Non-migratory.

Habitat
Open sites, pasture, grasslands, foothills, montane meadows, bogs, banks of watercourses, avalanche chutes, above treeline in alpine seeps and tundra (Scott 1986; Threatful 1988; Opler and Wright 1999; Glassberg 2001; Pyle 2002). In Glacier National Park, Montana reported from xeric and mesic montane meadows (Debinski 1993), in the Greater Yellowstone Ecosystem reported in wet to xeric montane meadows (Debonski et al 2013).

Food Habits
Larval food plants include Astragalus (multiple species), Hedysarum, Lathyrus (multiple species), Lotus, Lupinus (multiple species), Medicago, Melilotus, Oxytropis, Thermopsis, and Vicea (multiple species) (Scott 1986, 1992, 2006; Pyle 2002; Warren 2005; James and Nunnallee 2011). Adults feed on flower nectar (including Allium, Astragalus, Barbarea, Berberis, Cerastium, Erigeron, Eriogonum, Erysimum, Hymenopappus, Hymenoxys, Harbouria, Iris, Lepidium, Lesquerella, Linum, Lonicera, Medicago, Melilotus, Mertensia, Oxytropis, Phacelia, Physaria, Senecio, Thermopsis, Thlaspi), bird droppings, mammal dung, and mud (Pyle 2002; Warren 2005; Scott 2014).

Reproductive Characteristics
Females lay eggs singly on host plant flower buds, sometimes immature leaves (Scott 1986, 1992, 2006; James and Nunnallee 2011). Number of eggs per ovariole (1/8 of total) about 40 (Ehrlich and Ehrlich 1978). Eggs hatch in 4-6 days (depending on temperature), reach L2 instar in 3-4 days, reach L4 (or L5) instar and pupate 20-21 days (perhaps as much as 26 days) after oviposition, larvae wander off host plant to pupate at plant base, pupal stage overwinters (hibernates) up to 10 months (Scott 1979; Guppy and Shepard 2001; James and Nunnallee 2011). Larvae solitary, feed on flowers, leaves, fruits, do not build nests, are tended by ants (Formica, Myrmecocystus, Taponima) in the wild and captivity (Scott 1986; Ballmer and Pratt 1991; Warren 2005; James and Nunnallee 2011).

References
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Citation for data on this website:
Silvery Blue — Glaucopsyche lygdamus.  Montana Field Guide.  .  Retrieved on , from