www.ukbutterflies.co.uk

I believe the image below is a Darwin's Heath but would be grateful for correction if required. Taken in the French Alps in 2017.
Kevin.

Hi Kevin. This is a pearly heath, Coenonympha arcania. The best giveaway is the extent of the white on the underside hindwing, which reaches the cell. In Darwin's heath it does not reach the cell:

Darwin's heath:



Pearly heath:



The two taxa are very closely related and known to hybridise locally. Darwin's heath is itself considered to be hybrid in origin, between C. arcania and C. gardetta, and there is considerable genetic mixing between darwiniana and gardetta in Switzerland. It's all to do with the ice advancing and retreating during the ice ages and interglacials, leaving relic populations which evolved separately then remixed. My picture of Darwin's heath, above, is from south of the Simplon, where it is at its 'purest' (in Switzerland).

Guy

Thanks Guy. Spot on as ever.

Kevin.