Polyommatus nicias (Meigen, 1830)

Host plants:
The caterpillars live on Geraniaceae such as Geranium sylvestris and Geranium rivulare.

Habitat:
In central Europe Polyommatus nicias occurs only in alpine meadows, forb communities, shrub edges or swamps of the central and southern Alps up to 2600m above sea level.

Life cycle:
The adults fly in a single generation from June to August. Oviposition takes place on leaves and flowers of the host plant. The caterpillars overwinter half-grown. I observed half to fully-grown caterpillars in late May at about 2200m above sea level on the Täschalpe (Valais, Switzerland) together with very little larvae of Lycaena virgaureae (the latter at Rumex scutatus).

Endangerment factors:
In the upper elevations, Polyommatus nicias is only locally endangered. But in the lower elevations it is threatened by intensive farming (overgrazing, mowing), afforestation and overbuilding (tourism!).

Remarks:
Polyommatus nicias is found in the western central and southern Alps, as in Switzerland in the Valais and the Engadine. It is missing in the northern Alps. In addition, it also occurs in Scandinavia and northern Russia as well as locally in the Pyrenees.