Abstracts (first author)

Talk 

Competition driven ecological speciation in Lake Tanganyika cichlids

Author(s): Winkelmann K, Genner MJ, Rüber L

Summary:

Disruptive selection operating on different habitat use can lead to ecological speciation. However the selective forces are often unclear. In Lake Tanganyika the cichlid fish Telmatochromis temporalis has two morphs: a small-bodied "shell" breeding morph, and a large-bodied "rock" breeding morph. We first show that body size differences are heritable in laboratory-reared first generation offspring. Using mtDNA and AFLP data we then show populations are philopatic, and that these morphs have evolved repeatedly. We next tested for divergence on habitat preference using substrate choice trials on wild-caught fish. We found individual habitat preferences in the absence of other fish were tightly linked to body size with larger individuals using rock, and smaller individuals using shells, irrespective of collection habitat. However, medium-sized "shell" males also used rock when given a free choice, but the presence of large competitor "rock" males caused them to shift towards the less preferred shell habitat, and to pair assortatively. Thus, the results support competition as a crucial agent driving the dichotomous habitat use observed in nature. Ecological speciation is feasible because smaller fish are favoured on shell habitat but outcompeted on rocks, while larger fish are selected against on shell habitats by predators.


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Contacts

Chairman: Octávio S. Paulo
Tel: 00 351 217500614 direct
Tel: 00 351 217500000 ext22359
Fax: 00 351 217500028
email: mail@eseb2013.com

Address

XIV Congress of the European Society for Evolutionary Biology

Organization Team
Department of Animal Biology (DBA)
Faculty of Sciences of the University of Lisbon
P-1749-016 Lisbon
Portugal

Website

Computational Biology & Population Genomics Group 
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