FEMALE SEXUAL BEHAVIOR AS THE MECHANISM RENDERING AEDES AEGYPTI REFRACTORY TO INSEMINATION

1. Certain females of A. aegypti are refractory to insemination, either because they are too young or because of previous insemination. Earlier reports indicated that refractory females prevent insemination by expulsion of semen from the bursa copulatrix. The present work indicates that this is not the case.2. Three lines of evidence indicate that refractory females prevent insemination by failing to give the cues that lead to male ejaculation. First, males exposed to refractory females show no loss in their ability to inseminate. Secondly, refractory females exposed to males show no evidence of external sperm masses resulting from expulsion. Thirdly, refractory females placed with radioactive males show no increase in radioactivity, indicating no transfer of labelled semen. Since the forced-copulation technique overrides normal behavior of females, earlier data obtained using this technique are not relevant to normal insemination.3. Copulation by a mature virgin female is characterized by firm genital un...