A long temporal study of Red Queen dynamics in diploid-polyploid populations of Carassius gibelio
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| Year of publication | 2018 |
| Type | Appeared in Conference without Proceedings |
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| Description | Carassius gibelio, a member of Carassius auratus complex, is a specifi c cyprinid species exhibiting two forms of reproduction, sexual and asexual. It is a non-native, invasive fi sh species with more than fi fty years of history on the European continent. We hypothesized that parasite selection is one of the potential mechanisms contributing to the coexistence of the two reproductive forms of C. gibelio living in the same habitat. The Red Queen hypothesis describes host-parasite dynamics on the basis of negative parasite-mediated frequency dependent selection, which can represent one of the advantages of sexual reproduction over asexual reproduction. Following the Red Queen hypothesis, asexually reproducing organisms should be more susceptible to pathogen infection than sexually reproducing organisms, because they exhibit lower genetic variability in comparison to sexual form. We performed a four-year study to investigate the dynamics of parasite infection in C. gibelio. A total of 22 metazoan parasite species were found. However, our results showed similar levels of prevalence for all studied parasite species in both forms. Monogeneans represented the most frequently observed parasite group in both sexual and asexual forms. A total of 7 species of Dactylogyrus, 3 species of Gyrodactylus and Paradiplozoon homoion were identifi ed in C. gibelio. The maximum prevalence and the highest intensity of infection were found for three monogenean species Dactylogyrus dulkeiti, Dactylogyrus anchoratus, Gyrodactylus sprostonae in both forms of gibel carp. We detected that both reproduction forms were more infected by parasite species in the last year of investigation. However, the sexual form was more parasitized by ectoparasites in the fi rst and last years and less parasitized by nematodes in the last year when compared to the gynogenetic form. We concluded that the observed dynamics of parasite infection does not support the Red Queen hypothesis, because we failed to fi nd a signifi cantly higher level of parasite infection in the asexual form in any year of our investigation. Our study was also focused on the analysis of genetic variability of functional MHC genes. A total of 47 original sequences MHC IIB DAB genes were revealed. Individuals of both forms expressed the alleles of one locus (DAB1 or DAB3) or the alleles of both loci (DAB1 and DAB3). We also revealed some alleles specifi c to sexual form and alleles specifi c to gynogenetic females. However, we confi rmed that number of allelic types in gynogenetic females is reduced in comparison with sexual diploids. |
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