Species of the day: Comma

29 March 2020 | Posted in James Duncan
Species of the day: Comma
© James Duncan

By James Duncan

Learning and Engagement Officer

The Comma (Polygonia c-album) must surely be one of Britain's most distinctive butterflies - not necessarily for its wildly exotic colours, but certainly its unique shape. It's also one of our major butterfly success stories, having increased its population size by over 50% in the last 40 years. In stark contrast it was in such major decline during the late nineteenth and early twentieth century that it teetered on the edge of extinction. Up until the nineteenth century Comma caterpillars were largely reliant on Hop as a foodplant, though mass harvesting has long since diminished - this forced a switch in diet enabling it to thrive on the widespread abundance of Common (Stinging) Nettle instead. Unlike humans, the Comma may also be benefitting from the effects of climate change, helping its population to expand further Northwards. Whatever the reasons for its expansion, one thing's for certain, it's bucking the trend amongst UK butterflies. 

More than anything else, the Comma is undoubtedly best known for its cryptic camouflage. With its jagged heavily scalloped wings in a closed position, any resting or hibernating Comma does a superb impression of a dead leaf and an accurately decaying one at that. Amongst branches and leaves, it's almost entirely inconspicuous. The camouflage doesn't stop at the adults as the caterpillars bear a remarkable resemblance to a bird dropping, helping them to avoid predation. The naming of the Comma doesn't have anything to do with the shape of the wings, it's due to the white punctuation mark which adorns their underwing - a splash of interest on an otherwise shaded brown background.

The Comma can be seen all year round, displaying a propensity for basking. They're undoubtedly a powerful flyer, furious flaps interspersed with bouts of gliding. Helpfully for observation, they're also a predictable butterfly and the males have a tendency to return to the same perching spot after short flights. Look out for their territorial displays along woodland edges and open rides.

Comma2

Comma © James Duncan

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