Erebia sthennyo Graslin, 1850

Host plants:
The caterpillar lives on varius tussocks forming grasses such as Festuca and Deschampsia.

Habitat:
Erebia sthennyo inhabits rocky pastures and slopes of the high Pyrenees between 1700 and 2600m above sea level. Apparently mosaics of wetlands (rivers, marshy meadows) and rocks are preferred. Egg-laying is expected to occur in strong sun-exposed areas.

Life cycle:
The development is very similar to the closely related Erebia pandrose. First, the young caterpillar hibernates, then in the second year, the mature caterpillar. Pupation takes place in May or June immediately after the snow has melt. The adults fly from June to August with peak in early July.

Endangerment factors:
Erebia sthennyo is probably only little threatened.

Remarks:
Erebia sthennyo is endemic to the Pyrenees (Spain, France, Andorra), where it is absent only in the easternmost part. Here occurs the in the Alps common Erebia pandrose. This exclusion already suggests the very close relationship between the two taxa which also show few differences in ecology.

Hints on determination:
The pattern is only indistinct on hindwing lowerside (contrary to Erebia pandrose).