Do Wolbachia influence fecundity in Nasonia vitripennis?

This paper reports the influence of a vertically transmitted symbiont, Wolbachia, on host fitness in the parasitic wasp, Nasonia vitripennis. We measured fecundities of uninfected strains and strains infected with either two Wolbachia variants (wAv,wBv) or one (wAv or wBv). Preliminary tests suggested that double-infected females produce more offspring on average than uninfected females. However, further studies failed to yield consistent fitness effects. To control for host genetic effects, the genotype of the double-infected and uninfected strain was 'replaced' with three different host genetic backgrounds by introgression. Contrary to previous results, we found no convincing evidence for positive fitness effects of Wolbachia in Nasonia vitripennis, once host genetic background was controlled for. It can be concluded that under the experimental design used here, the fecundity effects associated with Wolbachia in N. vitripennis are small or absent.