Red Queen dynamics in the diploid-polyploid complex of Carassius auratus
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| Year of publication | 2017 |
| Type | Conference abstract |
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| Description | Carassius gibelio - member of Carassius auratus complex is a extraordinary cyprinid species exhibiting dual reproductive ways i.e. sexual way and asexual way termed gynogenesis. As four forms of C. auratus complex were described in the waters of Czech Republic, D-loop region of mtDNA was analysed to identify the specimens of C. gibelio, which represented the most abundant form. On the basis of the Red Queen Hypothesis, asexual form (or the most common asexual genotype) is a target of parasite adaptation due to the limited genetic variability. In contract, sexual reproduction by creating a wide range of genetically diverse forms is able to escape to parasites. As a result, we expected that genetically homogenous asexual form of C. gibelio is disadvantaged i.e. should be more parasitized when compared to the genetically variable sexual form. At the same time, we were interested in the response of the host immune system to the parasitic infection. The parameters of non-adaptive (i.e. respiratory burst, lysozyme activity and complement activity) and adaptive immunity (IgM antibodies) were compared between two forms in four consecutive years. A total of 7 species of Dactylogyrus, 3 species of Gyrodactylus and larval stage of Paradiplozoon homoion, 2 species of Nematoda, Trematoda and Crustacea, Pisciola geometra, larval stage of glochidium and Ichthyopthirius multifiliis were identified in C. gibelio. The maximum prevalence and the highest intensity of infection were found for the following monogenean species: Dactylogyrus dulkeiti, D. anchoratus and Gyrodactylus sprostonae in both forms of gibel carp. The similar level of parasite infection in both gynogenetic females and sexual individuals was found. However, our study revealed a temporal variation in parasite load in both forms which could potentially be explained by the dynamics of host-parasite interactions predicted by Red Queen hypothesis. Our study indicates significantly higher specific immunity expressed by IgM for 3n females when compared to diploid specimens. Concerning the haematological parameters, only erythrocyte count was clearly affected by ploidy status and haematocrit was influenced by sex. This suggests that asexual triploids dispose by lower cell count than diploid individuals; it can be compensated by larger cell size in triploid females. |
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