Prof. Dr. Gabriele Gerlach
Carl von Ossietzky Universität Oldenburg
Fakultät 5: Mathematik und Naturwissenschaften
Postfach 2503
26111 Oldenburg

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Speciation in the sea: coral reef fish diversity is driven by ecological speciation

Tuesday, 2nd June 2015, Hörsaal [R.B54], GEOMAR, Westufer

Abstract:

Evolutionary theory requires understanding of mechanisms that drive microevolution and maintain population divergence. Isolation of marine populations caused by large-scale geographic barriers cannot alone explain the high speciation rates and biodiversity of coral reef fishes with their larval dispersal that would predict genetic homogeneity. In a long term project we searched for other isolating mechanisms starting at small spatial scales that drive microevolution despite gene flow.

In my talk I will highlight that incipient speciation can be observed on the spatial scale of meters to few kilometers. Genetic analysis of a coral reef fish over ten generations at the Capricorn-Bunker group in the Great Barrier Reef, Australia, revealed five overlapping, phenotypically indistinguishable clades that can be considered different species inhabiting two different ecological niches: coral reef lagoons and coral reef slopes. Our data provide evidence that shortly after hatching larvae imprint on olfactory cues of their natal environment including their own population. Orientation behavior, divergent selection between ecological niches and population recognition contributes to natal recruitment and genetic divergence that can persist despite gene flow.