Wiltshire and Swindon Biological Records Centre

Comma - Polygonia c-album

Commas are named for the white comma mark on the underwing that looks like dead leaves; this helps to camouflage the adults as they hibernate.

Comma in Bently Wood, WSBRC/John Notman

 

Habitat

It can be seen in woodlands, woodland margins and hedgerows.

Description

A very distinctive butterfly with scalloped edges to its wings that are rich orange in colour with dark brown blotches. The upperparts of the wings are a dark, rich orange colour with speckled markings. The underparts look like dead leaves with the distinctive white comma-shaped mark.

The caterpillars of the Comma are black flecked with white and orange, they also have the appearance of bird droppings from a large white patch on their back, this help to protect them from predators.

Biology

There are two broods per year. The adults of the first brood are on the wing from March to July, the second brood in late August and September.

Green eggs are laid on the leaves of nettles, elm, hop, and willows and hatch after about three weeks. The caterpillars spin web on the undersides of the leaves and feed upon them until their camouflage has developed and they emerge from the webs. The caterpillars suspend their pupae and the adults emerge a few weeks later and mate immediately giving rise to the second brood.

However, not all the adults that emerge are sexually mature so spend their first summer feeding and then hibernate overwinter to mate the following year. This means the adults that emerge after hibernation in March consist of first and second brood adults. The form that overwinters has dark undersides to its wings, the form that develops directly to sexual maturity have lighter undersides to their wings.

Threats

During the early twentieth century the Comma was rare in Britain where it could only be found on the Welsh border; in 1920 there were only two known sightings. Since then it has undergone a dramatic re-expansion and is now common throughout Britain; the reason for this sudden expansion is unclear.