Second instar larvae (caterpillars) of the Peacock butterfly,Inachis Io,on a plant of stinging nettle,Urtica dioica. The larvae feed and rest communally. This thermoregulatory behaviour is shown by several butterfly species with black larvae. It results in raising the temperature of the larvae,enabling them to feed earlier in the day than would otherwise be possible. When ready to pupate,the larvae disperse,often walking many metres from their food plants in order to pupate individually on nearby trees,bushes or walls. The Peacock is a common and widespread butterfly in the UK,where it shows nomadic behaviour,but rarely migrates across seas. The eyespots on the wings of the adult (imago) are an effective defence mechanism,augmented by the butterfly's ability to produce a hissing sound by rubbing its wings together as it opens them to display the visual warning of the eyespots |