Conservation biology of specific biotic interactions: the case of the lycaenid butterfly Maculinea alcon

Biotic interactions broadly influent organismal evolution and diversity. For instance, the strong association with a specific plant in a large number of herbivorous insects and consequent host plant-driven evolution have been acknowledged to explain the high species richness of insects. Here, we ask, whether host-based specialization is always supported by lineage sorting, by focusing on three morphologically similar ecotypic forms of the lycaenid butterfly Maculinea alcon. These ecotypes use each not only a specific host plant, but they socially parasitize distinct ants and occur in different type of habitats: hygric low-elevation, xeric low-elevation, and xeric high-elevation. Whereas such a multiple ecological constraint might be theoretially supported by a genetic differentiation of each forms, no significant distinctive molecular traits were revealed so far using classical Sanger sequencing, microsatellite or allozyme markers. In this study, we use a dataset of 1,393 Single Nucleotide Polymorphisms (SNPs) loci obtained by whole-genome RAD-sequencing of 26 specimens originating from an area ranging from Western to Eastern Europe. We discuss the results in light of how conservation strategies should apply to population-level genetic polymorphisms, when resulting phenotypes develop in contrasting ecological habitats.