Peacock butterfly  (Inachis io)

This widespread and common species is not threatened. It is not listed under any conservation designations (2).

The beautiful peacock butterfly is a well-known and instantly recognisable species thanks to its unique patterning. The stunning eyespots, which earn this species its common name, frighten predators, or divert birds from attacking the body (1). In stark contrast to the brightly coloured upper surfaces, the undersides of the wings are dull brown (1). The sexes are similar in appearance, but females are slightly larger (3). The caterpillar, which grows to 4.2 cm in length, has a black, spine-covered body freckled with fine white spots (4).

This butterfly is widespread and common in the southern half of Britain, but becomes scarcer further north (2). It is widespread in Ireland, and occurs throughout much of temperate Europe, extending northwards to southern Scandinavia, but is absent from many areas of the extreme south. It also occurs in Asia, reaching Japan (2).

Peacock butterflies occur in a wide range of habitats, and are familiar garden visitors to buddleias (Buddleja davidii). The adults prefer to feed in open areas in woodlands, and breeding habitat typically consists of large patches of nettles (Urtica dioica and Urtica urens), in sunny areas sheltered by woodland or hedges (2).

Usually one generation is produced each year. Females lay eggs in groups underneath nettle leaves during May, after around two weeks the eggs hatch. The caterpillars live in groups, protected by a web of silk, before dispersing to pupate, hanging underneath vegetation (4). The adults emerge around two weeks later, in late July. They gather together at sources of nectar, building up reserves to see them through hibernation, which usually begins in September (2) and occurs in hollow trees and other refuges, including attics (3). They do not mate until the following year, emerging from hibernation as early as February, with peak emergence occurring in April. Males defend territories in sunny locations, and chase any females that pass by (2).

This species is not currently threatened.

No conservation action is targeted at this widespread and common butterfly.

For more on this species see: The Millennium Atlas of Butterflies in Britain and Europe (2001). By Asher, J., et al. Published by Oxford University Press. For more on butterflies and their conservation see the Butterfly Conservation website:
http://www.butterfly-conservation.org

• Hibernation: a winter survival strategy characteristic of some mammals in which an animal's metabolic rate slows down and a state of deep sleep is attained. Whilst hibernating, animals survive on stored reserves of fat that they have accumulated in summer. In insects, the correct term for hibernation is 'diapause', a temporary pause in development and growth. Any stage of the lifecycle (eggs, larvae, pupae or adults) may enter diapause, which is typically associated with winter.
• Pupate: the process of forming a pupa, the stage in an insect's development, when huge changes occur that reorganise the larval form into the adult form. In butterflies the pupa is also called a chrysalis.

1. Carter, D. (1992) Butterflies and moths. Dorling Kindersley, London.
2. Asher, J., Warren, M., Fox, R., Harding, P., Jeffcoate, G. & Jeffcoate, S. (2001) The Millennium Atlas of Butterflies in Britain and Ireland. Oxford University Press, Oxford.
3. Animal Diversity Web (30/10/02) http://animaldiversity.ummz.umich.edu/accounts/inachis/i._io$narrative.html
4. Carter, D. & Hargreaves, B. (1986) A field guide to caterpillars of butterflies and moths in Britain and Europe. William Collins & Sons Ltd, London.