Comparative population genetics of mimetic Heliconius butterflies in an endangered habitat; Brazil's Atlantic Forest

Abstract

AbstractBackgroundBrazil's Atlantic Forest is a biodiversity hotspot endangered by severe habitat degradation and fragmentation. Habitat fragmentation is expected to reduce dispersal among habitat patches resulting in increased genetic differentiation among populations. Here we examined genetic diversity and differentiation among populations of twoHeliconiusbutterfly species in the northern portion of Brazil's Atlantic Forest to estimate the potential impact of habitat fragmentation on population connectivity in butterflies with home-range behavior.ResultsWe generated microsatellite, AFLP and mtDNA sequence data for 136Heliconius eratospecimens from eight collecting locations and 146H. melpomenespecimens from seven locations. Population genetic analyses of the data revealed high levels of genetic diversity inH. eratorelative toH. melpomene, widespread genetic differentiation among populations of both species, and no evidence for isolation-by-distance.ConclusionsThese results are consistent with the hypothesis that the extensive habitat fragmentation along Brazil's Atlantic Forest has reduced dispersal ofHeliconiusbutterflies among neighboring habitat patches. The results also lend support to the observation that fine-scale population genetic structure may be common inHeliconius. If such population structure also exists independent of human activity, and has been common over the evolutionary history ofHeliconiusbutterflies, it may have contributed to the evolution of wing pattern diversity in the genus.