Host acceptance by three native braconid parasitoid species attacking larvae of the Mexican fruit fly, Anastrepha ludens (Diptera, Tephritidae)

Abstract

We studied the oviposition and host acceptance behavior of three braconid parasitoid species native to Mexico, Doryctobraconcrawfordi (Viereck), Opiushirtus (Fischer), and Utetesanastrephae (Viereck), with potential to be considered as biocontrol agents against tephritid fruit fly pests in the Neotropics. Third instar larvae of Anastrephaludens (Loew), with and without previous parasitization by conspecifics, were simultaneously offered to females of each species, and the individual behavior was video recorded to construct oviposition flow diagrams. The patterns of foraging and host acceptance were similar in the studied species; all rejected mostly parasitized hosts suggesting that this strategy is common in the guild of larval parasitoids attacking Anastrepha spp. The complete searching and host acceptance process took 2.2 ± 0.1 min (mean ± SE) in D.crawfordi, 1.7 ± 0.1 s in U.anastrephae and 1.5 ± 0.1 s in O.hirtus. Notably, because of toxins injected by parasitoid females during oviposition, the parasitized hosts experienced a transient paralysis of variable duration. Hosts attacked by U.anastrephae remained immobile for the shortest time (12.5 ± 1 min) (mean±SE), followed by D.crawfordi (20.5 ± 3.4 min) and O.hirtus (24.1 ± 2 min). Our data revealed a notable discrimination ability in all three species, and that behavioral differences lay mainly in the time of parasitization and in the duration of paralysis experienced by attacked hosts. This suggest that the three species could be valuable as biocontrol agents, but additional studies are necessary to better understand the advantages and limitations of each one as natural enemies of fruit fly pests.