Effects of time-dependent intraspecific competition on offspring survival in the butterfly, Anthocharis scolymus (L.) (Lepidoptera: Pieridae)

Effects of mothers' eclosion and oviposition timing on the survival of their offspring in the pierid butterfly Anthocharis scolymus (L.) was examined. I recorded the performance of individual eggs and larvae that differed in their mother's eclosion and oviposition timing in a natural population, where A. scolymus feeds on Turritis glabra (L.) Bernh. Eggs laid early in the season, and larvae emerging from these eggs, had higher survival than eggs laid later, and larvae emerging from eggs that were laid later in the season, the causal factor being egg cannibalism by larvae on the same host plant. Logistic regression showed that females eclosing early in the season had higher offspring survival than females eclosing later. I conclude that optimal timing of adult eclosion in A. scolymus is a trade-off between eclosing early with associated higher offspring survival but lower egg-laying rate, and eclosing later with associated lower offspring survival but higher egg-laying rate. Received: 4 August 1997 / Accepted: 19 October 1997