A comparison of larval survivorship in wild and introduced populations of the large copper butterfly ( Lycaena dispar batavus)

Abstract

A critical aspect in the viability of large copper ( Lycaena dispar) populations in Britain is the period of winter hibernation (diapause). Studies on captive-bred larvae, overwintering in England, showed that they suffered substantially greater mortality than did a Dutch population in its native habitat. Inter-habitat variance in survivorship, at both English and Dutch sites, was only marginally influenced by habitat features per se, although current management practices in the Netherlands may contribute significantly towards overwinter losses. Under identical field conditions in England, hibernal survival of wild-caught larvae, collected in the Netherlands, was superior to that of captive-reared British stock. Conversely, when larvae from both sources were ‘overwintered’ in captivity differences in recorded survivorship were not significant. From these two strands of evidence we tentatively infer a genetic divergence of the two stocks. Future re-introduction of this species should therefore involve direct translocation from wild populations rather than using captive-bred populations.