A new cytoplasmic incompatibility type due to Wolbachia in haplodiploid insects

Wolbachia are endosymbiotic bacteria infecting many arthropod species. Thei r main effect is cytoplasmic incompatibility (CI) when infected males are c rossed with uninfected females, leading to the death of embryos in diploid species and biasing the sex-ratio in haplodiploid species. In the latter, C I has just been described in Nasonia where haploidization of eggs allows th eir development in males, without reduction in fertility. Here, we demonstr ate that Wolbachia infecting a Drosophila parasitoid, Leptopilina heterotom a, induce high CI. Contrary to Nasonia, male production is not increased, d ue to the mortality of diploid eggs. The impact of the CI type on the dynam ics of host-population invasion by Wolbachia is discussed.