Published online by Cambridge University Press: 31 May 2012
The oviposition behavior of the pteromalid parasitoid Nasonia vitripennis (Walker) was investigated in an attempt to explain the difference in population density maintained on two species of host, the housefly, Musca domestica L., and the blowfly, Phaenicia sericata (Meigen). The behavior of a female wasp was significantly affected by the species of host to which she was exposed. When presented with 10 pupae for 24 hours she averaged 14.2 eggs on 3.0 housefly hosts and 8.3 eggs on 7.2 blowfly hosts of the same size.The importance of the alteration in behavior to the population density of Nasonia became apparent when the suitability of the two host species was examined. At all densities of eggs more wasps matured on blowfly pupae than on housefly pupae of the same size. Survival on both hosts decreased as the density of Nasonia eggs increased. The difference in egg distribution, coupled with lower survival on housefly pupae and at increased density suggests a considerably lower production by this parasitoid on housefly hosts, compared with that on blowfly pupae.