Geranium Argus - Eumedonia eumedon

Phylum: Arthropoda - Class: Insecta - Order: Lepidoptera - Family: Lycaenidae

The Geranium Argus is not found in Britain and Ireland. Its common name reflects the fact that it is restricted to places where wild Geranium species (Meadow Cranesbill Geranium pratensis, for example), its larval foodplants, are found.

Description

Male and female Geranium Argus butterflies are verysimilar, but females can usually be distinguished by the presence of at least a small region of orange around the trailing edge of the upper hindwings, whereas on the males it is all brown. The underside of both males and females have distinctive white rays (see picture below) extending from the end of the cell to the submarginal spots.

Distribution

On mainland Europe the Geranium Argus is native to the Alps and parts of Scandinavia, and its range extends through the Balkans and eastwards into Siberia.

Habitat

These little butterflies can be seen in flowery meadows in Scandinavia as well as on alpine slopes where Geranium species grow.

Lifecycle

Eggs are laid singly on the leaves of wild geraniums such as Geranium pratense and Geranium sanguineum. the Geranium Argus overwinters as a small caterpillar. In spring the caterpillar resumes feeding before pupating. A single brood occurs and adults can be seen on thw wing between May and August.

Etymology

The origin of the specific epithet eumedon is unclear to us. Any help would be much appreciated.

Acknowledgements

This page includes pictures kindly contributed by Rob Petley-Jones.

Studying butterflies and moths...