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

0431856 - ÚBO 2015 RIV GB eng J - Journal Article
Kotusz, J. - Popiolek, M. - Drozd, P. - de Gelas, K. - Šlechtová, V. - Janko, Karel
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.
Biological Journal of the Linnean Society. Roč. 113, č. 1 (2014), s. 220-235. ISSN 0024-4066. E-ISSN 1095-8312
R&D Projects: GA ČR GBP505/12/G112
Institutional support: RVO:68081766
Keywords : diploid-polyploid complexes * European distribution * habitat partitioning * niche shift * parasite-mediated coexistence * Red Queen hypothesis * spined loach * unisexuality
Subject RIV: EG - Zoology
Impact factor: 2.264, year: 2014

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 Cobitisteania asexual complex thus contributes to the view that persistence of sex may, as in many taxa, be driven by case-specific processes.
Permanent Link: http://hdl.handle.net/11104/0236388