ddRAD sequencing data to resolve the evolutionnary history of three Coenonympha butterflies

Interspecific crosses are becoming central elements in animal evolution theories in the last decade and new methods in population genomics and model testing now allow disentangling the complexity these events can bring into the reconstruction of species evolutionary histories. The phenomenon of hybridization is recognized to be involved in key evolutionary processes such as local adaptation, colonization of new environments, species diversification or extinction. We evaluated the consequences of hybridization in a complex of three Coenonympha butterfly taxa present in the Alps using together morphological, genetic and ecological analyses. Our results suggest that the Darwin’s Heath (C. darwiniana) probably originated through hybridization between the Pearly Heath (C. arcania) and the Alpine Heath (C. gardetta) with different parental contributions. The consequence of the hybrid genome is clear for Darwin’s Heath morphology which is completely intermediate between the parental species whereas its climatic niche seems more similar to the Alpine Heath one. The results also reveal a strong differentiation between two distinct Darwin’s Heath populations leading us to propose the splitting of the taxon in two different species.