Effects and implications of antibiotic treatment on Wolbachia-infected vine weevil (Coleoptera: Curculionidae)
1 The parthenogenetic weevil Otiorhynchus sulcatus was collected from five geographical locations in the U.S.A. All weevils from each location were infected by Wolbachia belonging to supergroup B.
2 We hypothesized that treatment with tetracycline, which has been used to clear Wolbachia infection, would influence the reproduction of Wolbachia-infected parthenogenetic O. sulcatus females. Tetracycline treatment of preovipositional O. sulcatus females specifically inhibited egg hatching but had no effect relative to controls on any other physiological trait.
3 Treatment with gentamicin, which reportedly has no effect on Wolbachia infection but is indistinguishable from tetracycline in inhibiting protein synthesis of other bacterial genera, did not influence egg hatching.
4 These findings strongly suggest that the inhibition of egg development results from the antibiotic effect on Wolbachia rather than by direct toxic effects on O. sulcatus physiology.
5 We speculate that Wolbachia may be necessary for normal development of O. sulcatus eggs and discuss the implications of these findings for O. sulcatus ecology.