Publication details

Interruption of the host-parasite co-adaptation by hybridization tested using the monogenean infection in cyprinids

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Year of publication 2017
Type Appeared in Conference without Proceedings
MU Faculty or unit

Faculty of Science

Description The host specificity is affinity of the parasite to the most suitable host species after the consequent process of host-parasite co-adaptation. Strict specificity of the monogenean parasites is linked to their specific adaptations to their fish host. Nevertheless, such host-parasite co-adaptation may be interrupted by host hybridization. Fish host hybridization and maternally inherited mitochondrial DNA are hypothesized to affect the level of parasite infection. Patterns of the parasite infection and distribution on hybridized fish have been recently investigated. However, different scenarios of the parasite infection in hybrids and their parental fish species have been observed. The aim of this study was to analyse the monogenean infection in the two phylogenetically related species, common bream (Abramis brama) and silver bream (Blicca bjoerkna), and their F1 hybrids. Breed lines of common bream, silver bream and their F1 hybrids were prepared for this study. All fish specimens resulting from experimental breeding were infected from the specimens of common bream and silver bream collected from the field. Fish were subjected to the dissection and all monogenean parasites were collected, fixed and identified. Similarity between monogenean infection of the parental species and hybrids with different maternal origins was evaluated using the Sorensen index. Higher monogenean abundance was found in parental species (common bream and silver bream) when compared to their hybrids which supports the hybrid resistance hypothesis. However, parasite species richness of the F1 hybrids was higher when compared to the pure species as previously demonstrated also in other studies comparing the level of parasite infection between parental species and their hybrids. The effect of the maternal origin on the monogenean abundance in fish hybrids was found. Specialist and generalist parasites of the parental species were presented in the hybrids with different maternal origins. Higher abundance of the specialist parasites of B. bjoerkna in the hybrids with different maternal origins was found. Nevertheless, Sorensen index revealed high similarity between the parasite composition of common bream and the hybrids with different maternal origins. The presence of the parental species-specific monogenean parasites in the hybrids might indicate interruption of the host-parasite system of co-adapted genes. These results may be explained by the different degree of the host-parasite co-adaptation in A. brama and B. blicca.
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