Competitiveness of Sperm in Female Fall Armyworms Mating with Normal and Chemosterilized Males123

Female Spodoptera frugiperda (J. E. Smith) were allowed to mate sequentially with chemosterilized (tepa) and fertile males to study sperm competition. The mating of a fertile male with a female previously mated to a sterile male eliminated the effect of the earlier mating. In the reverse combination, i.e., the last mating with a sterile male, average viability of eggs was reduced 50%. Individual females tended to exhibit an “all or nothing” response in egg viability.