Abstract
The oceanic islands have a special place in the study of species formation because they offer exceptional occasions to analyze the role of geographical barriers and ecology in processes of differentiation. The islands in the Indian Ocean have significantly contributed to the advancement of knowledge on speciation through the model Drosophila sechellia/mauritiana/stimulans, which has and still is playing a key role in the understanding of genetic processes that are involved in speciation. These islands constitute an advantageous environment for developing more research on species formation, in particular in the taxonomic groups for which the understanding of the biogeography is henceforth improved. In this project we aim to analyze the action of evolutionary forces (selection, drift, migration) and to identify the ecological and historical constraints (fragmentation, geographical barriers, paleoclimate, biotic interactions…) that have provoked the emergence of an extraordinary polymorphism in the feather coloration of a small endemic passerine in the Reunion and Mauritius called the Mascarene White-eye (Zosterops borbonicus). In the Reunion the species show four geographic morphs, which is very surprising considering the small size of the island (almost 10 times smaller than the islands where such a variability is usually encountered) and the dispersibility of the Zosterops. Using population genomic approaches we will examine the spatial structure of supposedly neutral genetic markers and quantitative characters selected potentially within a series of populations on the islands of Mauritius and Reunion. This will enable us to propose a general schema on the structuring of populations, and all the more on the importance in relation to the genetic drift and the selection in the phenotypic differentiation, the genetic flux and migrations between populations. Focus will be put on the diffusion of the results implemented among managers and the scientific community. This will be done using various means such as publications in national and international journals, participation in national and international symposiums, and dissemination of results to the National Park of the Reunion, the National Forests Office and other governmental services through partner n° 5 (SEOR).
France