The influence of female post-emergence behavior on the time schedule of male mate-locating in Pieris rapae crucivora

Previous theoretical studies and some empirical studies suggested that the factors which affect female availability should influence male reproductive behavior. We noticed the female post-emergence behavior as one such factor , and investigated how it might influence male reproductive strategy in the butterfly, Pieris rapae crucivora. In the field and the laboratory newly-e merged females stayed on the underside of leaves 2.5 hr after emergence bef ore they flew voluntarily into the open where they are more visible to male s. Time spent before initial flight correlated negatively with ambient temp erature, and initial flights increased significantly the possibility that t he female would be detected by males. To evaluate whether these results cou ld explain the time schedule of males' search for females in the field, fem ale availability was estimated by shifting the observed schedule of female emergence according to the relationship between initial flight and effectiv e cumulative temperature. The resultant female availability correlated well with temporal changes observed in the number of mate-seeking males. Therma l conditions may influence male reproductive behavior via female post-emerg ence behavior, as well as via male body temperature.