Habitat requirements affect genetic variation in three species of mayfly (Ephemeroptera, Baetidae) from South Africa.

This study investigates genetic diversity in three species of Ephemeroptera, one eurytopic and therefore widespread () and two stenotopic and thus endemic ( and ) species, all of which co-occur in the southern Great Escarpment, South Africa. Mitochondrial DNA was analysed to compare the genetic diversity between the habitat generalist and the two habitat specialists. showed no indication of population genetic structure due to geographic location, while both species revealed clear genetic differentiation between geographic localities and catchments, evident from phylogenetic analyses and high F values from AMOVA. In addition, the phylogenetic analyses indicate some deeper haplotype divergences within and that merit taxonomic attention. These results give important insight into evolutionary processes occurring through habitat specialisation and population isolation. Further research and sampling across a wider geographic setting that includes both major mountain blocks of the Escarpment and lowland non-Escarpment sites will allow for refined understanding of biodiversity and associated habitat preferences, and illuminate comparative inferences into gene flow and cryptic speciation.