The determinants of genetic diversity in butterflies

This is the final version. Available on open access from Nature Research via the DOI in this recordUnder the neutral theory, genetic diversity is expected to increase with population size. While comparative analyses have consistently failed to find strong relationships between census population size and genetic diversity, a recent study across animals identified a strong correlation between propagule size and genetic diversity, suggesting that r-strategists that produce many small offspring, have greater long-term population sizes. Here we compare genome-wide genetic diversity across 38 species of European butterflies (Papilionoidea), a group that shows little variation in reproductive strategy. We show that genetic diversity across butterflies varies over an order of magnitude and that this variation cannot be explained by differences in current abundance, propagule size, host or geographic range. Instead, neutral genetic diversity is negatively correlated with body size and positively with the length of the genetic map. This suggests that genetic diversity is determined both by differences in long-term population size and the elect of selection on linked sites.Biotechnology & Biological Sciences Research Council (BBSRC)European Research CouncilNatural Environmental Research Council (NERC)Institute of Evolutionary Biology at Edinburgh Universit