Butterflies of Keele
Small Tortoiseshell Aglais urticae
This used to be the archetypal butterfly of summer; a familiar sight to all. It still is quite common but numbers have fallen over recent years and much research is going on to find out the causes. One possible cause is from a parasite that frequents its larval foodplant the Nettle Urtica. Another possibility is poor overwintering due to the milder climate of late. This may seem perverse but milder winters can lead to attacks from fungus and moulds.
There are three broods with adults being on the wing from spring through to autumn. They also hibernate over winter.
There is some reinforcement of the population by immigrants. Adults visit thistles, Buddleia etc. and are a familiar sight.