Darwin's Heath - Coenonympha darwiniana

Darwin's Heath / Piedmont Heath

Coenonympha darwiniana / macromma

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Switzerland, July 2018

Coenonympha darwiniana

Switzerland, July 2011 (pure specimen, south of the Simplon)

Coenonympha darwiniana

Switzerland, July 2012

Coenonympha darwiniana

Switzerland, July 2019

Coenonympha darwiniana

Switzerland, July 2011 (both hybrid gardetta/darwiniana)

Switzerland, July 2008

Switzerland

Coenonympha darwiniana distribution

Distribution

These two taxa are treated by many authors as subspecies of the alpine heath, Coenonympha gardetta. Further, those who distinguish gardetta as a distinct species often conflate the two present taxa as subspecies of darwiniana. What is clear is that the three represent a complex of closely related taxa, capable of hybridising freely where they meet. The alpine heath, Coenonympha gardetta, overlaps with both these taxa but they do not have contact with each other. All three are mostly likely upland descendents of the lowland pearly heath, Coenonympha arcania, and the two treated on this page are probably the result of interglacial re-hybridisation of pearly heath with alpine heath.

In appearance, Darwin's heath and Piedmont heath are most like the pearly heath, with prominent yellow ringing around the white-pupilled ocelli - and usually a further dark ring outside the yellow. The white band is narrower, however, never reaching the cell. The ground colour of the underside is a richer brown than the brown-grey of alpine heath and the whole appearance is of a warmer butterfly. On average it flies at lower altitudes than alpine heath (though higher than pearly). In Valais (Switzerland), intermediates between alpine heath and Darwin's heath are common, with 'pure' individuals of the latter mostly south of the Simplon Pass.

These are butterflies of flowery, grassy hillsides, often seen around tracks, where they settle on the path or on low vegetation to either side. The caterpillars, which hibernate, feed on various grasses and the adults fly from June to August in a single generation.