Journal Article
Gradient evolution of body colouration in surface- and cave-dwelling Poecilia mexicana and the role of phenotype-assortative female mate choice.
Bierbach, D., Penshorn, M., Hamfler, S., Herbert, D. B., Appel, J., Meyer, P., et al.
Record Number:
3617
Year:
2013
Journal:
Biomed Research International
Pages:
1-15
Volume:
148348
Abstract:
Ecological speciation assumes reproductive isolation to be the product of ecologically based divergent selection. Beside natural
selection, sexual selection via phenotype-assortative mating is thought to promote reproductive isolation. Using the neotropical
fish Poeciliamexicana froma systemthat has been described to undergo incipient ecological speciation in adjacent, but ecologically
divergent habitats characterized by the presence or absence of toxic H2S and darkness in cave habitats, we demonstrate a gradual
change in male body colouration along the gradient of light/darkness, including a reduction of ornaments that are under both
inter- and intrasexual selection in surface populations. In dichotomous choice tests using video-animated stimuli, we found surface
females to prefermales fromtheir own population over the cave phenotype.However, female cave fish, observed on site via infrared
techniques, preferred to associate with surface males rather than size-matched cave males, likely reflecting the female preference
for better-nourished (in this case: surface) males.Hence, divergent selection on body colouration indeed translates into phenotypeassortative
mating in the surface ecotype, by selecting against potential migrant males. Female cave fish, by contrast, do not have a
preference for the resident male phenotype, identifying natural selection against migrants imposed by the cave environment as the
major driver of the observed reproductive isolation.
Times Cited:
1
Relevent Species: