Original Research ARTICLE
Relative influence of host, Wolbachia, geography and climate on the genetic structure of the Sub-Saharan parasitic wasp Cotesia sesamiae
- 1UMR8079 Ecologie, systématique et évolution (ESE), Université Paris-Sud, France
- 2UMR9191 Évolution, génomes, comportement et écologie (EGCE), France
- 3International Centre of Insect Physiology and Ecology (ICIPE), Kenya
- 4Institut de recherche pour le développement (IRD), France
- 5UMR7261 Institut de recherche sur la biologie de l'insecte (IRBI), France
The parasitoid lifestyle represents one of the most diversified life history strategies on earth. There are however very few studies on the variables associated with intraspecific diversity of parasitoid insects, especially regarding the relationship with spatial, biotic and abiotic ecological factors. Cotesia sesamiae is a Sub-Saharan stenophagous parasitic wasp that parasitizes several African stemborer species with variable developmental success. The different host-specialized populations are infected with different strains of Wolbachia, an endosymbiotic bacterium widespread in arthropods that is known for impacting life history traits, notably reproduction, and consequently species distribution. In this study, first we analyzed the genetic structure of C. sesamiae across Sub-Saharan Africa, using 8 microsatellite markers. We identified five major population clusters across Sub-Saharan Africa, which probably originated in the East African Rift region and expanded throughout Africa in relation to host genus and abiotic factors, such as Köppen-Geiger climate classification. Using laboratory lines, we estimated the incompatibility between the different strains of Wolbachia infecting C. sesamiae. We observed that incompatibility between Wolbachia strains was asymmetric, expressed in one direction only. Based on these results, we assessed the relationships between the direction of gene flow and Wolbachia infections in the genetic clusters. We found that host specialization was more influential on genetic structure than Wolbachia-induced reproductive incompatibility, which in turn was more influential than geography and current climatic conditions. These results are discussed in the context of African biogeography, and co-evolution between Wolbachia, virus parasitoid and host, in the perspective of improving biological control efficiency through a better knowledge of biological control agents’ evolutionary ecology.
Keywords: Cotesia sesamiae, Parasitoid wasp, Wolbachia, Genetic structure, Host specialisation
Received: 27 Jul 2018;
Accepted: 31 Jul 2019.
Copyright: © 2019 Branca, Le Ru, Calatayud, Obonyo, Musyoka, Capdevielle-Dulac, Kaiser-Arnauld, Silvain, Gauthier, Herniou, Gayral, Paillusson and Dupas. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Dr. Antoine Branca, UMR8079 Ecologie, systématique et évolution (ESE), Université Paris-Sud, Orsay, 91405, Île-de-France, France, email@example.com