Comma Butterfly

Polygonia c-album — the comma butterfly — is one of the most morphologically distinctive European butterflies and a flagship species of British butterfly conservation success. Adults are 4.5-5 cm wingspan with rich orange-and-black upperside wings (similar to small tortoiseshell), but with two highly distinctive features: the WING EDGES are dramatically RAGGED and irregular (small angular indentations and projections rather than the smooth curves of typical butterflies), and the underside of each hindwing carries a small white COMMA-SHAPED mark — the source of the species' common name. The combination of ragged wings + dark mottled brown underside makes the resting comma butterfly one of the most extreme dead-leaf mimics in European Lepidoptera — the irregular wing outline closely resembles the tattered edges of a wind-damaged dead leaf, and the dark mottled coloration matches forest-floor litter. The species has one of the most-cited population recovery stories in British butterfly history. Comma populations were nearly extinct in Britain by 1900 — only 1-2 small colonies remained in southern England — likely due to changes in caterpillar host plant availability (the species had historically depended on hop, Humulus lupulus, which was being replaced by other agricultural crops). Beginning around 1930, the species began a steady population recovery and northward range expansion, switching to stinging nettle (Urtica dioica) as the primary host plant. The recovery accelerated after 1970, and by 2000 the comma had reached Scotland — one of the most successful recent UK butterfly recoveries on record. The species is also famous for two adult morph forms: a 'normal' overwintering form with relatively dark underside, and a 'hutchinsoni' form with a brighter golden underside that develops only in caterpillars that experience long summer day-lengths.