ARS | Publication request: Genetic characterization for intraspecific hybridization of an exotic parasitoid prior its introduction for classical biological control

Submitted to: Molecular Insect Science International Symposium Proceedings
Publication Type: Proceedings
Publication Acceptance Date: July 10, 2011
Publication Date: October 2, 2011
Citation: Bon, M., Ris, N., Fauvergue, X., Malausa, J., Benvenuto, C., Jones, W.A., Jeanneau, M., Blanchet, A., Thaon, M., Warot, S. 2011. Genetic characterization for intraspecific hybridization of an exotic parasitoid prior its introduction for classical biological control. Molecular Insect Science International Symposium Proceedings. 2-5 October, 2011, Amsterdam, The Netherlands. P.3.69.

Technical Abstract: The successful establishment of an exotic parasitoid in the context of classical biological control of insect pests depends upon its adaptability to the new environment. In theory, intraspecific hybridization may improve the success of the establishment as a result of an increase in the available genetic variability and /or the production of heterotic genotypes. An experimental framework for testing such a hypothesis was developed by the French agency INRA in collaboration with EBCL. The study subject was the African endoparasitoid, Psyttalia lounsburyi, a candidate biological control agent of the olive fruit fly. Previous genetic studies revealed a genetic structure within the parasitoid’s African distribution, with two well-supported clades occurring in Kenya, Namibia and South Africa. The two most differentiated populations in Kenya and South Africa were chosen for hybridization studies. Distribution and prevalence of Wolbachia in P. lounsburyi was also assessed. Two Wolbachia variants belonging to super-group A were detected, and the infection status varied significantly across populations and time. Wolbachia infections of the parasitoid’s host, B oleae, are reported here for the first time, but were rare. Genetic similarities between the Wolbachia variants of the parasitoid and the fly host suggest that a horizontal transfer may have taken place. Two aposymbiotic study populations were obtained, owing to Wolbachia-induced cytoplasmic incompatibilities. Biological characteristics, including fitness of their hybrids, were compared with those of parental lineages. Preliminary observations showed that the hybrids did not outperform the two parental lineages. The results are discussed in light of the expected adaptability of the 43,000 P. lounsburyi which were recently introduced in southern France.