Introduction
There are about 100 species in the genus Erebia, distributed variously across the Holarctic region, with 46 species recorded in Europe.
Almost all species inhabit damp high altitude grasslands. Most species are dark brown and feature a series of white-centred black ocelli set within a suffused area of orange towards the outer part of both wings. The markings are repeated on the underside but are more subdued.
Erebia theano is found in the Altai mountains, Siberia and Mongolia.
Habitats
This species inhabits lush grassy glades and clearings in coniferous and deciduous woodland at elevations between about 1000-2000m.
Lifecycle
I have no data regarding theano. The majority of Erebia species lay their eggs singly at the base of blades of grasses or sedges. Erebia larvae normally enter hibernation in the 2nd instar. They overwinter deep at the base of grasses and may be buried under snow for several months. In the spring after the snows melt, they awaken and resume feeding, becoming fully grown by early May. They feed at dusk, high up on the grass blades, leaving nibbled notches which give away their presence. In poor spring seasons larval development may be very slow, and it is likely that some larvae are unable to complete their growth in a single season and may spend 2 successive winters in hibernation. Erebia pupae are usually formed within a very flimsy cocoon at the base of grass tussocks.
Adult behaviour
On sunny days males imbibe moisture at the edge of puddles in warm sunny weather. Both sexes nectar at Asteraceae.