Wolbachia infection and mating compatibility of two morphotypes of Anastrepha fraterculus

DEVESCOVI, F.; C.A. CONTE; AUGUSTINOS, ANTIONIOS; S.B. LANZAVECCHIA; CANCIO MARTINEZ, ELENA; SEGURA, D.F.; C. CÁCERES; BOURTZIS, KOSTAS

Congreso; 10th International Symposium on Fruit Flies of Economic Importance; 2018

Background: The nominal species Anastrepha fraterculus has been recently recognized as a complex ofcryptic species with at least 8 distinct morphotypes. Two morphotypes, theBrazilian-1 and Peruvian, have accumulated profound differences in the sexualbehavior and physiology, resulting in a marked reproductive isolation. Furthermore,these two morphotypes harbor different strains of the endosymbiont bacteria Wolbachia, which is known to affect reproductionin many invertebrate species. Cytoplasmic incompatibility (CI) is one of themost widespread effects and is characterized by the induction of an embryoniclethality producing mating incompatibility. Here, we focused on the potentialcontribution of Wolbachia to thereproductive isolation between Brazilian-1 and Peruvian morphotypes. Methods: Laboratory colonies of these two morphotypes, either infected with Wolbachia or cured with antibiotics, wereused to test uni- and bi-directional CI. In the former, the four possible combinationsof infection status and sex were crossed for each morphotype. Latency to mate andmating duration were assessed as pre-zygotic isolation variables. Egg hatch,pupation, adult emergence and sex ratio were studied as post-zygotic isolation variables.For bi-directional CI, both heterotypic and infected crosses, and theirrespective cured controls, were also tested through the aforementionedvariables.Results: Egg hatch was reduced in crosses involving cured females and infectedmales within each morphotype compared to the compatible crosses. Interestingly,this effect showed to be stronger in the Peruvian morphotype. Egg hatch in theinfected crosses between Peruvian females and Brazilian-1 males was higher thanthe other heterotypic (either infected or cured) crosses. Regarding the other variables,no clear effects were detected. Conclusions: Uni-directional CI ineach of the A. fraterculus morphotypeis suggested as a phenotypic effect due to the presence of Wolbachia. No evidence of bi-directional cytoplasmicincompatibility was detected. Unexplored aspects such as bacterial density, therole of the interaction with the genetic background and biochemical imbalancesdue to antibiotic treatment should be considered to identify whether thissymbiont has been involved in the speciation of this species complex.