Rearing of five hymenopterous larval-prepupal (Braconidae, Figitidae) and three pupal (Diapriidae, Chalcidoidea, Eurytomidae) native parasitoids of the genus Anastrepha (Diptera: Tephritidae) on irradiated A. ludens larvae and pupae

Abstract

The aim of this study was to ascertain if eight species of native larval-prepupal and pupal Anastrepha (Diptera: Tephritidae) parasitoids which have been recently domesticated and colonized (Aluja et al. in press) could be reared on irradiated larvae and pupae, and if such was the case, determine the optimal irradiation dose so that only adult parasitoids (not flies) would emerge. The species considered were: Doryctobracon crawfordi, Utetes anastrephae, Opius hirtus (all larval-prepupal braconids), Aganaspis pelleranoi, Odontosema anastrephae (both larval-prepupal figitids), Coptera haywardi, Eurytoma sivinskii and Dirhinus sp. (diapriid, eurytomid and chalcidoid pupal parasitoids). Eight-day-old A. ludens larvae or 3-day-old A. ludens pupae were irradiated with 0, 5, 10, 15, 20, 25, 30, 35, 40, 50, 60 and 70 Gy under free oxygen and then subjected to parasitoid attack. Emergence of the unparasitized host was completely halted at 20–25 Gy but such was not the case with the three braconid parasitoids that emerged even if subjected to doses as high as 70 Gy. In the case of the figitids, the emergence of the host and the parasitoids was completely halted at 20 and 25 Gy, respectively. Some parasitoid emergence was recorded at 5–15 Gy but at this irradiation dose, fly adults also emerged rendering the fly/parasitoid separation procedures impractical. Finally, in the case of the pupal parasitoids, A. ludens adults emerged from unparasitized pupae irradiated at 15 Gy. Beyond this dose, only parasitoids emerged. With the exception of the figitid larval-prepupal parasitoids, irradiation did not negatively affect adult longevity or fecundity. Our results show that parasitoid mass rearing with irradiated hosts is technically feasible.