Erebia pluto (Prunner, 1798)

Host plants:
The caterpillars live on various grasses of the screes like some Festuca spp.

Habitat:
Erebia pluto colonized sunny, sparsely vegetated scree of the Alps from about 180 m asl upwards. The glacier retreat due to global warming generates new habitats. But on the other hand, lower habitats get too warm for the butterfly. Erebia pluto occurs only very locally.

Life cycle:
The larva hibernates twice. The first winter is passed mostly in L3 (probably partly younger possible), the second in last instar L5. The larva then feeds again for an only short period an pupates quickly. Thus the butterflies can appear early in the mountain spring. Depending on the snow melt, the flight time begins already in mid-June, and lasts in later, cooler years until early/mid-August. The eggs are laid on stones, preferably bright ones. The caterpillars are occasionally found under stones (own observations in Valais and Silvretta), where the slightly pruinose pupae rest, too.

Endangerment factors:
Erebia pluto is only at little threat due to its occurrance in high elevations. Some populations can be affected by tourism infrastructure and reservoirs for water energy (e.g. Lüner See in west Austrian Rätikon shows both threats). Additionally, the global warming has probably at least ambigous results on Erebia pluto (see above).

Remarks:
The total distribution covers the Alps and the central Apennines (rarely).