Role of parasite load and differential habitat preferences in maintaining the coexistence of sexual and asexual competitors in fish of the Cobitis taenia hybrid complex |
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Authors: | Jan Kotusz Marcin Popiołek Pavel Drozd Koen De Gelas Vera Šlechtová Karel Janko |
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Institution: | 1. Museum of Natural History, Faculty of Biological Sciences, University of Wroc?aw, , Wroc?aw, Poland;2. Institute of Biology, Department of Invertebrate Systematics and Ecology, Wroc?aw University of Environmental and Life Sciences, , Wroc?aw, Poland;3. Faculty of Sciences, University of Ostrava, , Ostrava, Czech Republic;4. Research Institute for Nature and Forest (INBO), , Brussels, Belgium;5. Biogenomics, K.U. Leuven Research and Development, , Leuven, Belgium;6. Laboratory of Fish Genetics, Department of Vertebrate Evolutionary Biology and Genetics, Institute of Animal Physiology and Genetics, , AS CR, Libechov, Czech Republic;7. Institute of Vertebrate Biology, , AS CR, Brno, Czech Republic;8. Life Science Research Centre, Department of Biology and Ecology, Faculty of Natural Sciences, University of Ostrava, , Ostrava, Czech Republic |
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Abstract: | In the context of the paradoxical ubiquity of sex, we tested whether stable coexistence of sexual and asexual fish of the genus Cobitis is mediated by parasites, as asexual fish suffer more from parasitic infections because of their lower genetic variability the Red Queen hypothesis (RQH)], or by partial niche shift of the two strains differing in mode of reproduction. We did not find a clear correlation between infection risk with a helminth parasite and the proportion of sexuals, and we found similar infection rates among sexual females and co‐occurring asexuals in general, including the most frequent clone in particular. These results suggest that the mechanisms of the RQH are not directly engaged in stabilizing this asexual complex. On the other hand, the temporally stable gradient in sexual/asexual proportions along the river correlated with gradients in environmental parameters (physicochemical water parameters, velocity, and shading of the habitat) and turnover in the fish assemblage structure. Sexual and asexual forms thus appear to prefer different habitats. The Cobitis teania asexual complex thus contributes to the view that persistence of sex may, as in many taxa, be driven by case‐specific processes. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 113 , 220–235. |
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Keywords: | diploid polyploid complexes European distribution habitat partitioning niche shift parasite‐mediated coexistence Red Queen hypothesis spined loach unisexuality |
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