Arndt Telschow
(Center for Ecological Research, Kyoto University)

06/02/21, 13:30 at Room 3631 (6th floor of building 3 of the Faculty of Sciences)

Wolbachia is a group of intracellular bacteria that is widespread among insects, isopods, mites, and nematodes. They are responsible for various manipulations of their host reproduction system, including parthenogenesis, feminisation, male killing, and cytoplasmic incompatibility (CI). The most common of these manipulations is CI, an incompatibility between sperm and egg that typically results in the death of the zygote. It was suggested that Wolbachia induced CI could promote speciation in the host. We tested this idea using mathematical methods. We analysed a model with two parapatric host populations, each infected with a different Wolbachia strain that causes bidirectional CI. Our main findings are: (1) A stable coexistence of the two Wolbachia strains is possible even if there is substantial migration between the populations. (2) Wolbachia induced CI causes a reduction of the gene flow between the host populations. Further, we derived a simple formula describing this gene flow reduction. (3) Bidirectional CI selects for premating isolation and so reinforces genetic divergence between host populations. In summary, our results show that bidirectional CI can greatly enhance the genetical divergence between parapatric host populations. This supports the view that Wolbachia can promote speciation in their insect hosts.

Back: Japanese / English