Fecundity and Host Utilization of the Aphid Parasite Aphelinus Semiflavus (Hymenoptera: Aphelinidae) at Two Host Densities

The longevity, fecundity, and oviposition rates of Aphelinus semiflavus Howard were determined at densities of 20 and 60 pea aphid hosts per day. Host density had no significant effect on parasite longevity and total fecundity, but it did influence the mean daily oviposition rate (16.5 and 19.5 aphids/day at density 20 and 60, respectively) and the overall proportion of aphids parasitized (82.3% and 32.5%, respectively) during the period of maximum egg laying. The implications of a shift in the fecundity schedule to an earlier reproductive age are discussed.