Heath Sulphur
Colias chippewa W.H. Edwards, 1872

Diagnosis: The upperside of this species is bright yellow with a wide black border and, unlike most sulphurs, there is no black spot in the middle of the forewing. The hindwing underside is heavily dusted with dark scales, with the white central spot lacking a dark rim. Females are usually white above with a reduced black border, particularly on the hindwing. Wingspan 32 to 45 mm.

Subspecies: The nominate subspecies chippewa is found over most of the North American range; the darker subspecies baffinensis occurs on Baffin Island.

Range: This sulphur is widespread across northern Canada and Alaska, as well as northern Eurasia. In Canada it is found on the Labrador coast west through northern Quebec and Ontario. It is also found across the northern parts of the four western provinces and is widespread in Yukon, the Northwest Territories and Nunavut north to Victoria Island and Baffin Island.

Similar Species: Other similar sulphurs have a dark rim around the white spot on the hindwing underside.

Early Stages: The larvae are green with a yellow stripe along each side. They feed on Arctic Blueberry (Vaccinium uliginosum) and Dwarf Blueberry (V. caespitosum).

Abundance: The Heath Sulphur is common in the northern boreal-forest region and on the open tundra.

Flight Season: There is one brood that flies from mid-June to early August.

Habits: Colias chippewa occurs in areas where blueberry is common, especially in protected stream valleys in tundra areas, and in clearings in the northern parts of the boreal forest.

Remarks: The Heath Sulphur can easily be seen near Churchill, Manitoba, where it is considered one of the most common butterflies (Klassen et al., 1989).

© 2002

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