Reproductive dynamics of the parasitoid, Spalangi endius (Walker) (Hymenoptera: Pteromalidae), with particular reference to host-searching and host-acceptance behavior

Oviposition and related behaviour in the host searching and host acceptance repertoire of Spalangia endius (Walker) were examined to determine how such behaviour might be controlled by the presence of mature eggs in this parasitic insect. In all experiments, Musca domestica L. pupae were the hosts. Host searching was observed in glass petri-dish arenas containing a sawdust substrate, half of which was contaminated with the odour of mature host larvae. The effects on searching behaviour of a series of ovipositions by one set of parasitoid females could not be distinguished from a control group that did not oviposit. A study of burrowing indicated that one-quarter of the population sampled could not exploit hosts buried in the sawdust substrate. The portion of search time that was spent in antennal investigation of the substrate and burrowing in the substrate was found to increase with fecundity. The probability that given hosts would produce parasite progeny was predictable for one- and two-day-old females that were given a series of hosts to attack in succession; the second and seventh hosts always produced progeny. Mated females were more fecund than virgins; the patterns of oviposition observed in mated and virgin females suggested that mating releases oviposition inhibition.Science, Faculty ofZoology, Department ofGraduat