Aglais io, the European peacock, or the peacock butterfly, is a colourful butterfly, found in Europe and temperate Asia as far east as Japan. The peacock butterfly is resident in much of its range, often wintering in buildings or trees. It therefore often appears quite early in spring.
The peacock butterfly has figured in research in which the role of eyespots as an anti-predator mechanism has been investigated. The peacock is expanding its range and is not known to be threatened.
The butterfly has a wingspan of 50 to 55 millimetres (2 to 2+1⁄8 in). The base colour of the wings is a rusty red, and at each wingtip it bears a distinctive, black, blue and yellow eyespot. The underside is a cryptically coloured dark brown or black, mimicking a dead leaf.
There are two subspecies: A. io caucasica (Jachontov, 1912), found in Azerbaijan, and A. io geisha (Stichel, 1908), found in Japan and the Russian Far East.
The peacock can be found in woods, fields, meadows, pastures, parks, and gardens, from lowlands up to 2,500 metres (8,200 ft) elevation. It is a relatively common butterfly, seen in many European parks and gardens. The peacock male exhibits territorial behaviour, in many cases territories being selected en route of the females to oviposition sites.
The butterfly hibernates over winter before laying its eggs in early spring, in batches of up to 400 at a time. However, recent studies in Belgium have shown that peacock butterflies reproduce in two periods: early spring and early summer, and a possible third period in autumn. They found that peacock butterflies show flight peaks in early July and early August to early October, with the emergence of butterflies with good-conditioned wings, which shows signs of new offspring. The olive green eggs are ribbed. They are laid on both the upper parts and the undersides of leaves of nettle species and hops.[citation needed] The caterpillars hatch after about a week. They are shiny black with six rows of barbed spikes and a series of white dots on each segment. The chrysalis may be either grey, brown or green, and may have a blackish tinge. The caterpillars grow up to 42 millimetres (1+5⁄8 in) in length.
