About Colias hecla Lefèbvre, 1836
Colias hecla, commonly known as the northern clouded yellow or hecla sulphur, is a butterfly belonging to the family Pieridae. In Europe, this species occurs in northern Norway, Sweden, and Finland, at elevations up to 900 meters. Its range also includes Greenland, Alaska, the Northwest Territories, Yukon, Quebec, Labrador, Manitoba, the Chukot region, eastern Chukotka, and the Russian Far East. Adults have a wingspan measuring 36 to 46 millimeters. Females have a black band along the wing edges that is interrupted by many yellow "windows", unlike the solid black band seen in males. This species was first described from Greenland, where no other Colias species are found besides Colias hecla. Depending on location, adult butterflies fly from June to August. They inhabit moist tundra habitats. Larvae feed on species of the genus Astragalus, including Astragalus frigidus and Astragalus alpinus, as well as Trifolium repens. In areas where Astragalus species are absent, larvae are also known to feed on Salix arctica.
