Direct mate choice maintains diversity among sympatric cichlids in Lake Victoria |
| |
Authors: | O. Seehausen F. Witte J. J. M. Van Alphen N. Bouton |
| |
Affiliation: | Institute of Evolutionary and Ecological Sciences, University of Leiden, P.O. Box 9516, NL-2300 Leiden, The Netherlands |
| |
Abstract: | Mate choice may play an important role in animal speciation. The haplochromine cichlids of Lake Victoria are suitable to test this hypothesis. Diversity in ecology, coloration and anatomy evolved in these fish faster than postzygotic barriers to gene flow, and little is known about how this diversity is maintained. It was tested whether recognizable forms are selection-maintained morphs or reproductively isolated species by investigating in the field reproductive timing, location of spawning sites, and mate choice behaviour. There was a large interspecific overlap in timing of breeding and location of spawning sites, which was largest in members of the same genus. Behavioural mate choice of such closely related taxa was highly assortative, such that it is likely that they are sexually isolated species and that direct mate choice is the major force that directs gene flow and maintains form diversity. The results differ from what is known about recent radiations of other lacustrine fish groups where speciation seems to be driven by diverging microhabitat preferences or diverging timing of reproduction, but are in agreement with predictions from models of speciation by diverging mate preferences. |
| |
Keywords: | adaptive radiation mate recognition polymorphism reproductive isolation sexual selection speciation |
|
|