LARVAL COMPETITION AMONG THREE HYMENOPTEROUS PARASITE SPECIES ON MULTIPARASITIZED HOUSEFLY (DIPTERA) PUPAE

AbstractOnly one parasite species survived on most housefly (Musca domesticaL.) pupae multiparasitized by any two of Nasonia vitripennis(Walk.), Muscidifurax zaraptorK. & L., or Spalangia cameroniPerk. N. vitripennisand M. zaraptorwere both intrinsically superior to S. cameroniif the attacks on the hosts by their females preceded, were simultaneous with, or followed by up to 48 hours those by females of S. cameroni. N. vitripenniswas intrinsically superior to M. zaraptorif its attack preceded that by M. zaraptorby at least 24 hours; M. zaraptorsurvived when it oviposited before N. vitripennis; and neither species was consistently superior to the other when their attacks were simultaneous or that by N. vitripennisclosely preceded that by M. zaraptor. N. vitripennisoften survived on multiparasitized hosts because of its rapid development and rapid and thorough host utilization which caused its rivals to starve. In contrast, M. zaraptor?ssuccess was a consequence of its pr?dation on eggs and larvae of its competitors and to a lesser extent its moderately rapid development and host utilization. S. cameroniwas usually intrinsically inferior to both of the other species because, in spite of being predaceous on their larvae, it developed much more slowly and seldom attacked their eggs. The significance of these qualitative characteristics in insect parasites used in biological control programmes is discussed.