|scientific name Colias nastes |
common name Labrador Sulphur
Gravelly or rocky alpine tundra.
One yearly brood, flying between mid July and late August.
This dark, grey-green sulphur, with the underside discal spot streaked towards the outside, is not likely to be confused with any other sulphurs. Unlike all other sulphurs, male Labradors have the forewing dark border broken with pale blotches, a trait usually found only in female sulphurs. Alberta populations are subspecies streckeri, described from Lake Louise. The common name is rather a poor one, since only a small portion of this species' distribution is within Labrador.
The immature stages are incompletely known; mature larvae are dark green with a pink-edged lateral stripe (Bird et al. 1995). This species is known for its rapid flight over its rocky and often steep alpine habitat, making it difficult to observe and capture.
Not of concern.
Larvae feed on Oxytropis splendens on Redcap Mountain near Cadomin (Bird et al. 1995), and likely other alpine legumes. There are no published reports of adult nectar sources.
An Arctic - alpine species, occurring from northern Labrador across the arctic to Alaska and south in the western mountains to extreme northern Washington state and Montana (Layberry et al. 1998, Guppy & Shepard 2001).
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