Speckled wood (Pararge aegeria)

KingdomAnimalia
PhylumArthropoda
ClassInsecta
OrderLepidoptera
FamilySatyridae
GenusPararge (1)
SizeCaterpillar length: up to 2.7 cm (2)
Wingspan: 3.8 – 4.4 cm (3)

Not threatened (4)

The speckled wood is a common woodland butterfly (4). It is a brown butterfly with yellowish-orange spots on the wings and numerous eye-spots (3). The undersides of the wings are marbled, and are light and dark brown in colour. The two sexes are similar in appearance (3). The caterpillar is yellowish-green with a dark-green stripe along the back and lines along the sides (2).

This butterfly is widespread throughout Britain but becomes less common further north (2). In the last 200 years, this species has undergone dramatic changes in range. It disappeared from much of its range during the last half of the nineteenth and early part of the twentieth century, and was found only in south-west England, parts of Wales, and western Scotland. After the 1920s the species began to recolonise its former range, and this expansion is continuing today (4).

Found in shady woodland clearings and edges, hedgerows and scrub (2).

The speckled wood can be seen in dappled sunlight in woodlands. The male tends to perch in patches of sunlight, and intercepts intruding butterflies. They may also patrol an area in search of females. This species does not usually feed on flowers but males and females feed on honeydew produced by aphids up in the tree canopy (4).

There are typically three generations per year, but in Scotland there is usually just two. The flight-periods of the adults of each generation overlap, so they can be seen from March through to October (4). Females lay their eggs singly on leaf blades of the foodplants (Cock’s-foot Dactylis glomerata, couch-grass Agropyron repens and annual meadow-grass Poa annua). The caterpillars, which hatch after around ten days, feed at night or during the day (2). They are very well camouflaged against the blades of grass, thanks to their green colouration (4). Pupae form attached to the foodplant or to vegetation nearby. The speckled wood can overwinter either as a caterpillar or as a pupa, an unusual situation in a butterfly.

This species is not threatened at present, but is increasing in range. This may be the result of the decline in coppicing. The decrease in this ancient form of woodland management has benefited this species, which prefers shady woodlands. Coppicing allows sunlight to filter through into woodlands managed in this way (4).

Conservation action has not been targeted at this common butterfly.

For more on butterflies, their conservation and details of how to get involved see: Butterfly Conservation:
http://www.butterfly-conservation.org.uk

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.

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact: arkive@wildscreen.org.uk

  1. National Biodiversity Network Species Dictionary (January2004): http://www.nhm.ac.uk/nbn
  2. Carter, D. & Hargreaves, B. (1986) A field guide to caterpillars of butterflies and moths in Britain and Europe. William Collins & Sons Ltd, London.
  3. Still, J. (1996) Collins Wild Guide Butterflies and Moths of Britain and Europe. HarperCollins Publishers, London.
  4. 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.