Euphydryas aurinia debilis

Valais, Switzerland, July 2006

Valais, Switzerland, July 2005

Valais, Switzerland, July 2004

Valais, Switzerland, July 2004

Valais, Switzerland, July 2004

Valais, Switzerland, June 2003

E Switzerland, July 2003

A badly worn example.

This is sometimes treated as a separate species from M. a. aurinia. It flies at high altitudes in the Pyrenees and Alps. It is much smaller than aurinia and lacks much of the orange. The upperside dark markings are very regular and solid, confining the yellowish ground colour to small regular bands. The undersides are also highly distinct lacking much of the orange of aurinia. They really do look like different species.

At one place in Valais, Switzerland, I found aurinia at 2000m flying beside a wet meadow in mid June. About 500m away in late June I found debilis flying over a dry mountain meadow. Finding two subspecies so close together is unusual as they would normally be expected to interbreed. Perhaps the differing flight time may help prevent this and also the different habitat but it does rather lend weight to the argument that they should be treated as separate species. I wonder if the early season in 2003 helped to produce an early debilis showing the form of aurinia, completely destroying the separate species argument. I'll have to go back another year to see if the two colonies show the same distinctions. I note that some people do refer to debilis as a separate species: Euphydryas glaciegenita.

Marsh Fritillary - debilis