THE COST OF BEING COMMON: EVIDENCE FROM NATURAL DAPHNIA POPULATIONS |
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Authors: | Justyna Wolinska Piet Spaak |
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Affiliation: | Indiana University, Department of Biology, 1001 East 3rd Street, Bloomington, Indiana 47405;Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland, and Institute of Integrative Biology, ETH Zurich, 8092 Zürich, Switzerland;E-mail:;E-mail: |
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Abstract: | The Red Queen coevolutionary hypothesis predicts that parasites drive oscillations in host genotype frequencies due to frequency-dependent selection where common hosts are at disadvantage. However, examples of this phenomenon in natural populations are scarce. To examine if the Red Queen theory operates in the wild, we studied the genetic structure of populations of the crustacean waterflea ( Daphnia ), in relation to their infection levels, for which we collected multiple samples from a variety of lakes. The most common clone in a given population was often underinfected. This advantage, however, did not remain stable over time. Instead, the most common clone decreased in frequency over subsequent generations, indicating that parasites can track common clones. Such decreases were not observed in uninfected populations. Moreover, host clonal evenness was higher across the set of infected lakes compared to uninfected lakes; suggesting that any common clone is selected against when parasites are present. These results strongly suggest that Red Queen dynamics do operate in the wild. |
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Keywords: | Coevolution genetic diversity parasitism Red Queen |
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