prof. dr. M.E. Maan
Divergent visual adaptation and sexual selection in cichlid fish
PhD student: Shane Wright
In the cichlid fish of Lake Victoria (East Africa), bright male coloration affects both inter- and intraspecific female mate choice, indicating that sexual selection is important for species differentiation. At the same time, the fish show extensive variation in colour vision, apparently as an adaptation to their diverse visual environments. Possibly, visual adaptation to different light conditions changes female perception of male coloration, such that females that inhabit different light environments will develop different colour preferences.
We investigate the role of visual adaptation in cichlid speciation. We use a combination of field observations (characterising under water light conditions and haplochromine colour diversity across communities) and laboratory experiments (testing the effects of visual adaptation on visual behaviour in foraging and mate choice contexts).
The role of parasites in host speciation: testing for parasite-mediated divergent selection at different stages of speciation in cichlid fish (with Ole Seehausen, UBern and Eawag, Switzerland)
PhD student: Tiziana Gobbin
Parasites are an important agent of selection in wild animal populations. Theory suggests that coevolution between parasites and their hosts can lead to the origin of divergently adapted populations of both, and to the origin of new species of hosts and parasites.
In this project, we will study the role of parasites in the radiation of Lake Victoria cichlids, one of the most species-rich freshwater fish communities in the world. These fish have adapted to various different habitats and ecological niches and they carry a large diversity of parasites. This makes it an ideal model system to investigate the effects of parasite-host coevolution on the origin of species.
What is the role of phenotypic plasticity in species diversification? Plasticity may help to colonise new niches, but on the other hand it may weaken the strength of divergent selection. We address this question by studying visual plasticity in cichlid fish. We combine phylogenetic comparative analysis (species richness patterns) with experimental investigation of visual plasticity (retinal pigment expression) and its fitness consequences (growth and survival under competition).
|Last modified:||01 December 2018 4.56 p.m.|