The role of Cardinium-induced cytoplasmic incompatibility and hybrid incompatibilities in the reproductive isolation between two closely related Encarsia (Hymenoptera: Aphelinidae) species

Encarsia pergandiella (Hymenoptera: Aphelinidae) is an important parasitoid of whiteflies distributed in a number of geographically differentiated populations that differ in reproductive mode and endosymbiotic bacteria infection. Whereas E. pergandiella from California appears uninfected, the endosymbiotic bacterium Cardinium causes thelytoky in a population from Brazil, and cytoplasmic incompatibility (CI) in a sexual population of from Texas. E. pergandiella from California and Texas have subtle but consistent morphological differences, and show partial to complete reproductive isolation from each other, in spite of genetic distinctiveness suggesting that the two populations are distinct species. The aim of this work was to evaluate the role of CI-inducing bacteria and genic incompatibilities in the reproductive isolation and competitive interactions of these parasitoid populations. The level of reproductive compatibility between Cardinium-infected and uninfected E. pergandiella was assessed by both pre-zygotic (mating preferences) and post-zygotic (crossing results) incompatibilities. Results will be presented.