Revealing community assembly through barcoding: Mediterranean butterflies and dispersal variation.

In Focus: Scalercio, S., Cini, A., Menchetti, M., Vodă, R., Bonelli, S., Bordoni, A., … Dapporto, L. (2020). How long is 3 km for a butterfly? Ecological constraints and functional traits explain high mitochondrial genetic diversity between Sicily and the Italian Peninsula. Journal of Animal Ecology. https://doi.org/10.1111/1365-2656.13196. Biotic and abiotic factors can shape geographical patterns of genetic variation within species, but few studies have addressed how this might generate common patterns at the level of communities of species. Scalercio et al. (2020) have combined mtDNA sequence data and life-history traits, to reveal a repeated pattern of genetic structure between Sicilian and southern Italian butterfly populations, which are separated by only 3 km of ocean. They reveal how intrinsic species traits and extrinsic environmental constraints explain this pattern, demonstrating an important role for wind. Moreover, the inclusion of almost 8,000 georeferenced sequences reveals that, in spite of also being present in southern Italy, almost half of Sicilian butterfly species are more closely related to populations from other parts of Europe, Asia or North Africa. We provide further discussion on the biogeographic barrier they identify, and the potential of community-level DNA barcoding to identify processes that structure genetic variation across communities.