Experimental evidence for trait utility of gill raker number in adaptive radiation of a north temperate fish

Rösch, Christian; Lundsgaard-Hansen, Bänz; Vonlanthen, P; Taverna, A.; Seehausen, Ole (2013). Experimental evidence for trait utility of gill raker number in adaptive radiation of a north temperate fish. Journal of Evolutionary Biology, 26(7), pp. 1578-1587. Wiley 10.1111/jeb.12166

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North temperate fish in post-glacial lakes are textbook examples for rapid parallel adaptive radiation into multiple trophic specialists within individual lakes. Speciation repeatedly proceeded along the benthic – limnetic habitat axis, and benthic – limnetic sister species diverge in the number of gill rakers. Yet, the utility of different numbers of gill rakers for consuming benthic vs. limnetic food has only very rarely been experimentally demonstrated. We bred and raised families of a benthic – limnetic species pair of whitefish under common garden conditions to test whether these species (i) show heritable differentiation in feeding efficiency on zooplankton, and (ii) whether varia- tion in feeding efficiency is predicted by variation in gill raker numbers. We used zooplankton of three different size classes to investigate prey size dependency of divergence in feeding efficiency and to investigate the effect strength of variation in the number of gill rakers. Our results show strong interspecific differences in feeding efficiency. These differences are largest when fish were tested with the smallest zooplankton. Importantly, feeding efficiency is significantly positively correlated with the number of gill rakers when using small zooplankton, also when species identity is statistically controlled for. Our results support the hypothesis that a larger number of gill rakers are of adaptive significance for feeding on zooplankton and pro- vide one of the first experimental demonstrations of trait utility of gill raker number when fish feed on zooplankton. These results are consistent with the suggested importance of divergent selection driven feeding adaptation during adaptive radiation of fish in post-glacial lakes.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Department of Biology > Institute of Ecology and Evolution (IEE)
08 Faculty of Science > Department of Biology > Institute of Ecology and Evolution (IEE) > Aquatic Ecology

UniBE Contributor:

Rösch, Christian and Seehausen, Ole

Subjects:

500 Science > 570 Life sciences; biology

ISSN:

1010-061X

Publisher:

Wiley

Language:

English

Submitter:

Marcel Häsler

Date Deposited:

12 Apr 2014 10:58

Last Modified:

15 Jan 2015 11:01

Publisher DOI:

10.1111/jeb.12166

BORIS DOI:

10.7892/boris.45002

URI:

https://boris.unibe.ch/id/eprint/45002

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