Artificial transfer of a thelytoky-inducing wolbachia endosymbiont between strains of the endoparasitoid wasp asobara Japonica (Hymenoptera: Braconidae)

Infection with Wolbachia is known to induce diploidization of haploid eggs and enables the production of females from unfertilized eggs. Although there have been several attempts to achieve the artificial horizontal transfer of thelytoky-inducing Wolbachia in parasitoid wasps, the artificial induction of thelytoky has generally been unsuccessful. In this study, we used two strains of Asobara japonica as study materials—one infected with thelytoky-inducing Wolbachia and the other not. We investigated methods of artificially inducing thelytoky by transferring thelytoky-inducing Wolbachia from wasps of the infected strain (the donor wasps) to wasps that had been cured of Wolbachia and to wasps of the uninfected strain (the recipient wasps). To examine the efficiencies of various methods of transfection, we compared the survival and infection rates of recipient wasps that received microinjections at the pupal and adult stages and in different body parts. We also examined the infection rate of the recipients due to cannibalism of Wolbachia-infected pupae. Among those methods, only microinjection at the adult stage resulted in the successful artificial horizontal transfer of Wolbachia, and some of the Wolbachia-infected wasps showed incomplete thelytoky. A low Wolbachia titer in the artificially infected wasps may explain why the thelytoky was incomplete.