Biology

In most areas of Britain, there are typically two generations each year, but in Scotland there is usually just one. Adults that have hibernated through the winter emerge in March or April; the small tortoiseshell is therefore one of the first butterflies to be seen each spring (2). Females lay eggs in batches underneath the leaves of the foodplants (2). The eggs hatch after around 10 days, and the caterpillars live in groups protected by a silk web. After the final moult the caterpillars disperse, and pupate hanging from plant stems or other objects (3). The adults emerge after around two weeks (3); adults of the second generation hibernate in buildings, caves and hollow trees (2), and reproduce the following spring (3).