The caterpillar lives on grasses (mainly Molinia and Carex). It has been found almost exclusively on Carex panicea near Munich.
Coenonympha oedippus is mostly found in wet river valley Molinia meadows or other fen stocks with small harrows (Carex) and moor grass (Molinia). Typically are interspersed, very loose reeds (Phragmites). Dense reed beds and eutrophic tall herb stocks or hay meadows (Cirsium oleraceum meadows) are significantly avoided. In some places (Southern Alps) Coenonympha oedippus inhabits obviously to a lesser extent also dry, steep, often bounded by forest and hardly mown hillside meadows or clearings.
The caterpillar overwinters (brown discoloration) and is fully-grown in May. The moths fly from early June to early August, with a peak in most years in late June/early July. The moths fly very slowly around, the males often patrolling looking for females and sit only occasionally in the sunshine and then mostly for a short moment on the grass. The females, however, often sit in the vegetation and attach their eggs on blades of grass, etc. Flowers are visited in both sexes only comparatively rarely. But aphid excretions and guttation drops of grasses and herbs seem to be important ressources.
Endangerment: threatened with extinction
Coenonympha oedippus is one of the most endangered butterflies in Europe at all. So the specis is quasi extinct in Germany, Switzerland and Austria. In the northern Alps (with neighbouring countries), there are only in Liechtenstein two still better populations in fens, one of which is also already influenced by eutrophication, parcelling and disturbance of the water balance with subsequent immigration of neophytes (Solidago!).
The most important threats are destruction of wetland habitats by eutrophication, agricultural intensification, overbuilding and succession after abandonment of traditional extensive use (autumn cutting).
Coenonympha oedippus occurs from southwest France (Northern Spain?) across central and Eastern Europe and Asia (especially south Russia) to Japan.
In Europe, the last, often highly isolated populations, are located especially in south-western France (Les Landes, best occurrence) and in the Southern Alps (particularly Northern Italy). In Eastern Europe (eastern Poland, etc.) and in Liechtenstein there are only small remainders. In Germany a last small population is known from Bavaria.
Hints on determination:
Coenonympha oedippus can be confused with Coenonympha hero, but the latter has orange borders of the ocellion hindwing underside. Aphantopus hyperantus which is omnipresent in the sites is larger without lead coloured marginal stripe on hindwing underside.