Comma (Polygonia c-album)
|Size||Wingspan: 4.4 - 4.8 cm (2)|
Caterpillar length: up to 3.5 cm (3)
Not threatened (4)
The comma is a beautiful, common butterfly. The wings have scalloped edges, and the undersides are strikingly similar in appearance to dead leaves; an excellent camouflage for hibernating adults (4). The upper surface of the wings have a rich orange hue with dark brown blotches and the common name ‘comma’ refers to the presence of a prominent white comma-shaped marking on the underwing (2). The black caterpillars are flecked with white and orange, and have a large white patch on the back that creates a remarkable resemblance to bird droppings, a trait that protects them from potential predators (3).
Widespread and common throughout most of England and Wales but is extinct in Scotland, having once been found as far north as Fife (4). During the early twentieth century this butterfly was rare in Britain, being found only around the Welsh border; it has since experienced a dramatic re-expansion for unclear reasons (4). Elsewhere, the comma occurs throughout most of Europe and across Asia, reaching Japan. It is also found in North Africa (4).
Found in woodland margins, open woodlands and hedgerows (3) (4).
The comma is bivoltine, which means that two generations are produced each year (3). It has a complicated life-cycle, with adults of the first brood flying in July, and those of the second flying in late August and September (4). Eggs are laid singly on leaves of the foodplants (nettles, elm, hop, currants and willows). They hatch after two or three weeks and initially the caterpillars spin webs on the undersides of the leaves. Once their bird-dropping camouflage has developed, they emerge into the open (4). The caterpillars suspend their pupae from stems and 2-3 weeks later the adults emerge. Some of these adults mate immediately, giving rise to the second brood of adults in late August or September. However, other adults of the first brood are not sexually mature after emerging from pupation; they spend their first summer feeding and then hibernate, mating the following year. As a result, the adults that emerge after hibernation consist of a mix of first and second brood adults (4).
This species is not threatened at present; it is undergoing an expansion in range (4).
Conservation action has not been targeted at this common species.
For more on invertebrates, their conservation and details of how to get involved see: Buglife, the invertebrate conservation trust:
For more on butterflies see: The Millennium Atlas of Butterflies in Britain and Ireland by: Asher, J., Warren, F., Fox, R. Harding, P., Jeffcoate, G. & Jeffcoate, S. Published by Oxford University Press.
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- Bivoltine: (also known as ‘double-brooded’) insect life cycle that takes 12 months to be complete, but involves two generations in that time. The first generation adults lay eggs that give rise to those of the second generation. The second generation overwinters either as an egg, larva, pupa or adult.
- Pupae: stage in an insect’s development when huge changes occur, which reorganise the larval form into the adult form. In butterflies the pupa is also called a chrysalis.
- Pupation: the process of becoming a pupa.
- National Biodiversity Network Species Dictionary (January2004): http://www.nhm.ac.uk/nbn
- Still, J. (1996) Collins Wild Guide Butterflies and Moths of Britain and Europe. HarperCollins Publishers, London.
- Carter, D. & Hargreaves, B. (1986) A field guide to caterpillars of butterflies and moths in Britain and Europe. William Collins & Sons Ltd, London.
- Asher, J., Warren, F., Fox, R. Harding, P., Jeffcoate, G. & Jeffcoate, S. (2001) The Millennium Atlas of Butterflies in Britain and Ireland. Oxford University Press, Oxford.