Barzman, M.S. 1992 . Host-handling strategies in parasitoids of Black Scale (Saissetia oleae (Olivier)) (Homoptera: Coccidae). University of California, Berkeley 107 pp.

Notes: [Ph.D. Thesis; L.E. Caltagirone, Advisor.] Host handling, i.e., host assessment, oviposition, and host feeding, was examined in detail in Metaphycus bartletti Annecke & Mynhardt, M. lounsburyi (Howard), and M. zebratus Mercet (Hymenoptera: Encyrtidae). Host handling is compared in these three species, other closely related species, and species in the genus Coccophagus Westwood (Hymenoptera: Aphelinidae) which are parasitic on soft scales. Oviposition behavior is described and its significance with respect to host-parasitoid evolution is discussed. The data suggest that the hardness of the host integument is a factor which influenced the evolution of oviposition mechanisms and host range. Nutrition of adult parasitoids is addressed with particular attention to host feeding. From this study, a characterization of the adult life history of several parasitoids emerges and its relation to host feeding is discussed. M. lounsburyi and M. zebratus, two closely-related species with adults and eggs of similar morphology and size, are compared. Host feeding was not found to confer higher fecundity to M. zebratus. Other life history traits examined in M. zebratus, such as prolonged adult lifespan, lead to the hypothesis that this species is adapted to an ecological niche in which suitable hosts are frequently unavailable. The ability of M. lounsburyi and M. zebratus to coexist with ants is compared. It was found that the rapid oviposition and absence of host feeding in M. lounsburyi, in comparison to other Metaphycus species, is accompanied by a greater ability to remain on a plant in the presence of ants. Under experimental conditions, these traits conferred greater success in drilling and ovipositing in M. lounsburyi. It is hypothesized that M. lounsburyi evolved these traits in response to pressure from ants while M. zebratus evolved free from this pressure. It is proposed that M. helvolus (Compere), escapes ant interference by attacking early scale instars.