First instar larvae (caterpillars) of the Peacock butterfly,Inachis Io,on a plant of stinging nettle,Urtica dioica. Early instars spin a web over the tip of a growing stem,or as here,over stem leaves. The web provides shelter and a site at which the skin may be safely shed. When the food source within the web is exhausted,the group of larvae moves on to a fresh site,producing a fresh web. 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 |