Colias hecla Lefèbvre, 1836

Host plants:
The larvae feed on Astragalus alpinus.

Habitat:
Colias hecla inhabits places with short-growing, gappy tundra vegetation, usually sunny slopes up to 1000m. The butterfly is also recorded from plains and rarely from sand banks of Arctic rivers.

Life cycle:
The adults fly rather late between late June and early August. They appear most often from early to mid-July. Males patrol on the sparse slopes. The larva usually hibernates twice, first when still small (supposedly L2-L3) and in the penultimate instar again. In late June 2020 I recorded a larva in the penultimate instar which became mature after some days as well as one in the antepenultimate instar which started hibernation after the next moult in the penultimate instar (N-Finland, Kilpisjärvi). In years with very bad weather reputedly also the pupa may be able to hibernate.

Remarks:
Colias hecla is found around the Arctic in polar Europe, Greenland, northern North America and northern Asia. In Europe it occurs in N-Russia and N-Scandinavia (N-Sweden, N-Norway and N-Finland). In Asia it is also found in some mountain ranges in the center of the continent (e.g. Transbaikalia).