Pytoseiid mites and Wolbachia

Wolbachia are a group of intracellular alpha-proteobacteria that are widespread symbionts in arthropods. Wolbachia are associated with the reproductive tissue and usually maternally transmitted through the egg cytoplasm. They alter the reproduction of their arthropod hosts to their own benefit in various ways. Most commonly they mediate cytoplasmic incompatibility (CI), which is the phenomenon where infected males become reproductively incompatible with non-infected females. Among many other arthropods, Wolbachia has been recently detected in several predaceous mite species, e.g. in the well-known biocontrol-agent Phytoseiulus persimilis (Acari, Phytoseiidae), where it causes nonreciprocal reproductive incompatibility associated with low numbers of viable eggs and a strongly male biased sex ratio. The present study aims at uncovering whether female mate choice of P. persimilis is influenced by Wolbachia infection. The major objectives are: (1) To determine whether non-infected P. persimilis females loose fitness (i.e. a measure of the contribution of a given genotype to the subsequent generation relative to that of other genotypes) when they mate with males infected by Wolbachia as compared to non-infected females that mate with non-infected males. (2) To test whether non-infected P. persimilis females prefer to mate with non-infected males when given a choice between males infected with Wolbachia and non-infected males.(3) To assess whether non-infected P. persimilis females that mated with males infected with Wolbachia tend to remate with non-infected males to avoid fitness loss in terms of viable daughter production. The results of the study will not only provide insights in the behavioral ecology of phytoseiid mites, in particular sexual selection, but also have strong implications to using P. persimilis in pest management, e.g. whether Wolbachia has an impact on the performance of P. persimilis as biocontrol agent and whether Wolbachia can be used as driving mechanism to insert useful genes in a population.