Wolbachia-induced parthenogenesis in a genus of phytophagous mites

The vertically transmitted endosymbiotic bacterium Wolbachia modifies host reproduction in several ways in order to enhance its own spread. One such m odification results in the induction of parthenogenesis, where males, which are unable to transmit Wolbachia, are not produced. Interestingly, parthen ogenesis-inducing Wolbachia have only been found within haplodiploid insect s and it is not known whether this exclusivity is the result of functional constraints of Wolbachia. Here we find a unique pattern of Wolbachia infect ion that is associated with parthenogenesis in six species within the phyto phagous mite genus Brvobia. Through antibiotic treatment we show that, in t wo species, BrYobia praetiosa and an unidentified species, the Wolbachia in fection is strictly associated with parthenogenesis. Microsatellite loci sh ow the mechanism of parthenogenesis to be functionally apomictic and not ga mete duplication, with progeny identical to their infected mother. Crossing experiments within B. praetiosa showed no evidence of sexual reproduction. These results are discussed with reference to the distribution of partheno genesis-inducing Wolbachia and the diversification of the Bryobia genus.