Data from: Differences in male coloration are predicted by divergent sexual selection between populations of a cichlid fish

Female mating preferences can influence both intraspecific sexual
selection and interspecific reproductive isolation, and have therefore
been proposed to play a central role in speciation. Here, we investigate
experimentally in the African cichlid fish Pundamilia nyererei if
differences in male coloration between three para-allopatric populations
(i.e. island populations with gene flow) of P. nyererei are predicted by
differences in sexual selection by female mate choice between populations.
Second, we investigate if female mating preferences are based on the same
components of male coloration and go in the same direction when females
choose among males of their own population, their own and other
conspecific populations and a closely related para-allopatric
sister-species, P. igneopinnis. Mate-choice experiments revealed that
females of the three populations mated species-assortatively, that
populations varied in their extent of population-assortative mating and
that females chose among males of their own population based on different
male colours. Females of different populations exerted directional
intrapopulation sexual selection on different male colours, and these
differences corresponded in two of the populations to the observed
differences in male coloration between the populations. Our results
suggest that differences in male coloration between populations of P.
nyererei can be explained by divergent sexual selection and that
population-assortative mating may directly result from intrapopulation
sexual selection.