Consideration of Eurytoma sivinskii Gates and Grissell, a eurytomid (Hymenoptera) with unusual foraging behaviors, as a biological control agent of tephritid (Diptera) fruit flies

A recently discovered Mexican parasitoid species of Eurytomidae (Hymenoptera), Eurytoma sivinskii Gates and Grissell, has the unique behavior, for its family, of attacking tephritid fruit fly pupae (Anastrepha spp.) on or in the soil. Adults burrowed but did so rarely, thus pupae on the soil surface were significantly more vulnerable than those underground. Females facultatively hyperparasitized other larval-prepupal and pupal parasitoids such as Opius hirtus (Braconidae), Coptera haywardi (Diapriidae) and Pachycrepoideus vindemiae (Pteromalidae). While E. sivinskii developed in the pupae of various other Anastrepha, including, A. serpentina and A. striata, it also attacked cyclorraphous Diptera such as Musca domestica and a tachinid species. The number of expected female offspring (Ro) was 44.3 when measured as eclosed eggs (i.e., that became larvae) and 34.3 when measured as the number of emerged adults, and the intrinsic rate of natural increase (rm) was 0.34. This is high relative to other fruit fly parasitoids and suggests that E. sivinskii could rapidly exploit a clumped resource. We conclude that the marginal ability of E. sivinskii to attack buried pupae and the environmental risks it poses through its broad host range and capacity for hyperparasitism make it a poor candidate for tephritid biological control.