Wolbachia facilitates the reproduction of a parthenogenetic ladybird

Wolbachia is a bacterial endosymbiont that is primarily transmitted from mother to offspring. As a result of the increased transmission by females, strains that favour the production of female offspring, such as by inducing parthenogenesis, are selected for. Here, we assess the role of Wolbachia in recently discovered parthenogenetic populations of the ladybird Nephus voeltzkowi by treating females with an antibiotic. Our results demonstrate that the treatment decreases Wolbachia load, subsequently reducing egg production and development among parthenogenetic females, while having no effect on sexual females. Wolbachia load and reproduction then rebound when the treatment is removed. This suggests that the Wolbachia infection is necessary for successful reproduction in the parthenogenetic females, and it may play a two-part role by facilitating egg laying and late embryo development. The co-occurrence of Wolbachia infection and parthenogenesis in N. voeltzkowi, as well as Wolbachia's effect on host reproduction, makes this a likely candidate for Wolbachia-induced parthenogenesis outside of haplo-diploids. Understanding how Wolbachia impacts diverse insect reproductive systems can shed light on the extent to which these bacteria can affect hosts for their own gain.