Natural History of Hamlet Communities Reveals Incipient Speciation Due to Color Morphology

The hamlets (Hypoplectrus spp, Serranidae) constitute a distinctive marine model system for the study of sex allocation, the evolution of mating systems, mutual mate choice and speciation, and no less than six new species have been described in the last few years. Nevertheless, relatively little is known about the natural history of hamlet communities. Here, we aim to fill this gap by gathering data on the ecology, behavior, morphology and population genetics of the hamlets from Bocas del Toro (Panama). We report clear-cut differences between sympatric species in terms of color pattern, mate choice, abundance, body size and diurnal behavior, subtle differences in habitat use, and low but highly significant levels of genetic differentiation at microsatellite loci (F_st estimate = 0.011-0.029). Altogether, this data indicate that sympatric hamlets behave largely as distinct species notwithstanding their high genetic and ecological similarity, and that hamlet communities are more complex and diverse than usually appreciated.