Potential interactions between pupal and egg- or larval-pupal parasitoids of tephritid fruit flies

Abstract

This study investigated the interactions of the pupal fruit fly parasitoid, Dirhinus giffardii Silvestri, with each of four egg- or larval-pupal fruit fly parasitoids: Fopius arisanus (Sonan), Diachasmimorpha longicaudata (Ashmead), Diachasmimorpha kraussii Fullaway, and Psyttalia concolor (Szépligeti) in Hawaii. F. arisanus attacks host eggs, whereas the other three attack host larvae; all four parasitoids emerge from host puparia. D. giffardii attacked host puparia that had been previously parasitized by all of the other four parasitoids. Attacks by D. giffardii on young fly puparia in which the secondary (parasitoid) host pupae had not fully formed resulted in high offspring mortality of D. giffardii compared with those developing on older host puparia, in which the host pupae had fully formed. Adult D. giffardii that developed on secondary host species were smaller and had higher mortality than those reared from the primary host, the Mediterranean fruit fly, Ceratitis capitata (Wiedemann). Developmental times of male and female D. giffardii were not affected by the host species. D. giffardii preferred to attack older rather than younger host puparia. D. giffardii also preferred to attack the primary rather than the secondary host species and invested more female offspring in primary than in secondary host species. Because of its nature of facultative hyperparasitism, D. giffardii may pose significant nontarget risks to other primary fruit fly parasitoids.