CHANGES IN OVIPOSITION BEHAVIOR OF THE ECTOPARASITOIDS NASONIA-VITRIPENNIS AND MUSCIDIFURAX-ZARAPTOR (HYMENOPTERA, PTEROMALIDAE) WHEN USINGDIFFERENT SPECIES OF FLY HOSTS, PRIOR OVIPOSITION EXPERIENCE, AND ALLOSPECIFIC COMPETITION

Oviposition behavior was used to determine if handling time was a reli able indicator of host suitability for oviposition by the ectoparasiti c wasps, Nasonia vitripennis (Walker) and Muscidifurax zaraptor Kogan & Legner, on pupae of Sarcophaga bullata Parker, the black blow fly, P hormia regina (Meigen), and the house fly, Musca domestica L. Oviposit ion behavior of both parasitoids was composed of a series of stereotyp ic and interdependent events or phases. The duration of behavioral eve nts preceding puparium penetration was influenced by host species, ind icating that host recognition depends on some external cue associated with the fly puparium. Total handling time was stereotypic regardless of host species or the number of eggs laid on a host, suggesting that the amount of time invested by N. vitripennis and M. zaraptor in ovipo sition does not predict clutch size or host preference. When N. vitrip ennis and M. zaraptor were held together at low host densities, female s of N. vitripennis reacted aggressively and interfered with all ovipo sition attempts by M. zaraptor. Aggression by N. vitripennis toward M. zaraptor subsided when host density was increased, presumably because this was a less competitive situation.