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Montana Field Guide

Montana Field Guides

Arrowhead Blue - Glaucopsyche piasus


Global Rank: G5
State Rank: S5

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General Description
[From Ferris and Brown 1981; Scott 1986; Opler and Wright 1999; Glassberg 2001; Pyle 2002] Forewing 1.4-1.7 cm. Uppersurface of both sexes dull blue with irregular black margins, lack dark cell-end bars, female with variable amounts of orangish scaling toward wing margins. Undersurface wing fringes white, checkered black at tips of veins, a pattern of black spots on gray background, distinctive white patches of submarginal and postmedian arrowhead-shaped marks directed inward toward one outstanding white arrowhead on the disk.

Phenology
One flight; late May to early July in most of range, late March to May in southern California (Scott 1986). Late March to May in southern and lowland California, May to June and July farther north and at higher elevations (Glassberg 2001). Early April to late August in Oregon and Washington (Pyle 2002, Warren 2005), mid-May to early July in British Columbia (Guppy and Shepard 2001).

Diagnostic Characteristics
Best determined by the hindwing undersurface with distinctive white patches of submarginal and postmedian arrowhead-shaped marks directed inward toward one outstanding white arrowhead on the disk.

Species Range
Montana Range

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Range Comments
Southern British Columbia and Alberta south through the western US mountains to southern California, Nevada, northern Arizona, northwestern New Mexico, east to the Black Hills of South Dakota (Scott 1986; Opler and Wright 1999; Glassberg 2001); mostly 1829 m to 3048 m elevation in Colorado (Brown 1957; Scott and Scott 1978; Ferris and Brown 1981), 60 m to 2438 m elevation in Oregon (Warren 2005), to 1250 m elevation in British Columbia (Guppy and Shepard 2001). Locally rare to uncommon (Glassberg 2001).

Summary of Observations Submitted for Montana
Number of Observations: 1

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Relative Density

Recency

 

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



Migration
Non-migratory.

Habitat
Montane openings, ponderosa pine woodland, sagebrush flats, foothill canyons (Scott 1986; Opler and Wright 1999; Glassberg 2001). In Glacier National Park, Montana reported from subalpine transition areas and above treeline in alpine terrain (Debinski 1993); the report from alpine terrain seems unlikely and may be in error.

Food Habits
Larval food plants include Astragalus and several species of Lupinus (Scott 1986, 1992, 2006; Warren 2005; James and Nunnallee 2011). Adults feed on flower nectar (including Astragalus, Barbarea, Ceanothus, Chrysothamnus, Cirsium, Conium, Cryptantha, Erigeron, Eriogonum, Geranium, Glycrrhiza, Jamesia, Phacelia, Sedum, Senecio), damp ash, and mud (Scott 1986, 2014; Pyle 2002; Warren 2005).

Reproductive Characteristics
Females lay eggs singly on host plant flower buds, sometimes on leaves and stems (Scott 1986, 1992; James and Nunnalee 2011); larvae feed mostly on host plant flowers and fruits, less often on leaves. Eggs hatch in 2-3 days (depending on temperature), L1 instar burrows into flowers or buds, L2-L4 instars associated with fruits encased in pods. Larvae build no nest, are attended by ants, overwinter as pupae (Scott 1979, 1986; Warren 2005, James and Nunnallee 2011). Males patrol throughout the day near host plants to seek females (Scott 1975b, 1986).

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