FLUCTUATION OF PROTANDRY IN ECLOSION OF ANTHOCHARIS-SCOLYMUS (LEPIDOPTERA, PIERIDAE) - CAN MALES ECLOSE OPTIMALLY UNDER EVOLUTIONARY EQUILIBRIUM

To elucidate the adaptive significance of protandry (males eclosing ea rlier than females), the eclosion patterns of males and females in a p opulation of the univoltine pierid butterfly Anthocharis scolymus (But ler) were studied by a mark-release-recapture method over 6 yr. We tes ted whether the findings could be explained by the evolutionarily stab le strategy model for optimal male eclosion. Protandry occurred every year and the average protandry for the 6-yr period was not significant ly different from the protandry predicted by the model. However, male eclosion patterns fluctuated from year to year; although the male eclo sion patterns for 3 yr indicated a fairly close fit to the optimal ecl osion predicted by the model, those for the remaining 3 yr were signif icantly earlier than the model predicted. We discuss the factors that may have caused male eclosion earlier than the prediction of the model .