Most butterflies in Lithuania overwinter in the egg, caterpillar, or pupal (chrysalis) stage; however, some species survive the winter as adults. These butterflies appear early in spring. In March, when snow and ice can still be found in forests, the first spring species can already be seen basking in sunny clearings: common brimstones, small tortoiseshells, and european peacock butterflies.
Common brimstone butterflies (Gonepteryx rhamni) are among the longest-lived butterflies. Emerging in the second half of June, they remain active throughout the summer, then overwinter – most often in the forest floor among fallen leaves—and reappear early in spring. The caterpillars of these butterflies feed on the leaves of buckthorn or alder buckthorn.
Small tortoiseshell butterflie‘s (Aglais urticae) caterpillars feed on the leaves of the common nettle. There are two generations of this species each year. The first generation emerges in late May or the first half of June and flies for about a month, until late July. The second generation is active from mid-July until late autumn; these butterflies then overwinter and reappear in spring to lay eggs. They often spend the winter in unheated places such as farm buildings or house attics.
Peacock butterflies (Aglais io) emerge in July and remain active until late autumn. They often choose various buildings and cellars as places to overwinter. After wintering, the butterflies can be seen flying again until the end of June. Their caterpillars feed on the leaves of hops and nettles. Since the butterflies lay eggs in large clusters – often a hundred or more in one place – the newly hatched caterpillars live in large groups and can heavily defoliate their host plants.
