Variation in parasite resistance of Arctic charr,Salvelinus alpinus,between and within sympatric morphs |
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Authors: | Anssi Karvonen Samantha V Beck Skúli Skúlason Bjarni K Kristjnsson Camille A Leblanc |
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Institution: | 1. Department of Biological and Environmental Science, University of Jyvaskyla, Jyvaskyla Finland ; 2. Department of Aquaculture and Fish Biology, Hólar University, Sauðárkrókur Iceland ; 3. Galloway Fisheries Trust, Newton Stewart Scotland |
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Abstract: | Genetic variation in resistance against parasite infections is a predominant feature in host–parasite systems. However, mechanisms maintaining genetic polymorphism in resistance in natural host populations are generally poorly known. We explored whether differences in natural infection pressure between resource‐based morphs of Arctic charr (Salvelinus alpinus) have resulted in differentiation in resistance profiles. We experimentally exposed offspring of two morphs from Lake Þingvallavatn (Iceland), the pelagic planktivorous charr (“murta”) and the large benthivorous charr (“kuðungableikja”), to their common parasite, eye fluke Diplostomum baeri, infecting the eye humor. We found that there were no differences in resistance between the morphs, but clear differences among families within each morph. Moreover, we found suggestive evidence of resistance of offspring within families being positively correlated with the parasite load of the father, but not with that of the mother. Our results suggest that the inherited basis of parasite resistance in this system is likely to be related to variation among host individuals within each morph rather than ecological factors driving divergent resistance profiles at morph level. Overall, this may have implications for evolution of resistance through processes such as sexual selection. |
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Keywords: | adaptive radiation breeding coloration freshwater fish ecotype host– parasite interaction immunogenes speciation trematode |
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