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Montana Field Guides

Labrador Sulphur - Colias nastes

Potential Species of Concern
Native Species

Global Rank: G5
State Rank: S2S3

Agency Status

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General Description
[From Ferris and Brown 1981; Scott 1986; Opler and Wright 1999; Glassberg 2001; Pyle 2002] Forewing 2.0-2.4 cm. Small for a sulphur. Wing fringes tinged with pink. Uppersurface dingy white to dirty greenish-yellow, black borders of both sexes enclose greenish-yellow submarginal spots; undersurface of forewing greenish with few submarginal black spots, hindwing greenish, the discal cell spot edged in pink and often smeared or strongly pointed outwardly.

One flight; late June to early August northward, mid-July to mid-August in Labrador, July and August in Alberta (Scott 1986). Mainly mid-July to early August (Glassberg 2001). July and August in the Rocky Mountain states (Ferris and Brown 1981), early July to early September in Washington (Pyle 2002), probably mid-July to mid-August in British Columbia (Threatful 1988; Guppy and Shepard 2001).

Diagnostic Characteristics
Probably best determined by a combination of habitat, small size for sulphur, pale pinkish fringes, uppersurface dingy white to dirty greenish-yellow with black borders of both sexes enclosing greenish-yellow submarginal spots; undersurface greenish, hindwing with discal cell spot edged in pink and often smeared or strongly pointed outwardly.

Species Range
Montana Range Range Descriptions


Range Comments
Holarctic. In North America, northern Alaska east across arctic Canada including the Canadian Arctic Archipelago to Ellesmere Island, south in the interior mountains of British Columbia and Rocky Mountains to north-central Washington and northwestern Montana (Ferris and Brown 1981; Ferris 1985; Scott 1986; Opler and Wright 1999; Glassberg 2001; Guppy and Shepard 2001); 1829 m to 2530 m elevation in Washington (Pyle 2002), 2194 m to at least 2499 m elevation in southeastern British Columbia (Threatful 1988). In Montana, reported from Flathead and Glacier counties (Kohler 1980; Stanford and Opler 1993), especially Glacier National Park (Ferris 1985; Debinski 1993), and Teton County in 2005 at about 2560 m elevation (FLMNH Lepidopterists' Society database). Rare to uncommon (Glassberg 2001).


Above treeline on wind-swept tundra ridges, scree, fellfield, dry alpine slopes, tree-line meadows; at high latitude in arctic willow communities, tundra grassland, sedge and cottongrass, well-drained ridge tops, open spruce-tamarack woodland (Oosting and Parshall 1978; Ferris and Brown 1981; Scott 1986; Threatful 1988; Opler and Wright 1999; Glassberg 2001; Pyle 2002; Ezzeddine and Matter 2008; Leung and Reid 2013). In Glacier National Park, Montana reported above treeline in alpine terrain (Debinski 1993).

Food Habits
Larval food plants include Astragalus, Hedysarum, Oxytropis (multiple species), and Lupinus (Oosting and Parshall 1978; Ferris and Brown 1981; Scott 1986; Guppy and Shepard 2001). Adults feed on flower nectar, including Achillea, Agoseris, Arnica, Astragalus, Campanula, Epilobium, Erigeron, Haplopappus, Hedysarum, Oxytropis, Potentilla, Saxifraga, Sedum, and Solidago (Oosting and Parshall 1978; Ezzeddine and Matter 2008).

Reproductive Characteristics
Limited information. Females probably deposit eggs singly on host plants. No information on developmental rates of larval instars, L3 instars hibernate (diapause) and possibly as older instars (may be biennial, spending two winters as larvae), no information on pupation location and pupal duration (Scott 1979, 1986; Pyle 2002). Males patrol throughout the day over a broad area in search of females (Oosting and Parshall 1978).

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Labrador Sulphur — Colias nastes.  Montana Field Guide.  .  Retrieved on , from