A short term benefit for outcrossing in a Daphnia metapopulation in relation to parasitism

Ebert, Dieter and Altermatt, Florian and Lass, Sandra. (2007) A short term benefit for outcrossing in a Daphnia metapopulation in relation to parasitism. Interface : journal of the Royal Society, 4 (16). pp. 777-785.

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Official URL: https://edoc.unibas.ch/80864/

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Because host parasite interactions are often specific to the host and parasite genotype, it may be important whether a host reproduces by selfing or outcrossing. The latter is associated with higher genetic diversity among the offspring and may reduce parasite success. Here, we test whether outbred offspring of Daphnia magna have an advantage over selfed offspring in the presence of a parasite transmitted from mothers to offspring. Using outdoor mesocosms, we set up monoclonal and polyclonal host populations of D. magna infected with a prevalence of 100% with the horizontally and vertically transmitted microsporidian parasite Octosporea bayeri. These populations diapaused after sexual reproduction and hatchlings were screened for signs of O. bayeri. Parasite prevalence was 98.9% for hatchlings from the monoclonal treatment, but only 85.2% among the hatchlings from the polyclonal populations, indicating a short-term benefit for outbreeding. This bene. t occurs, we hypothesize, not owing to inbreeding depression, but because the vertically transmitted parasite is less able to establish itself in the relatively new genetic environment of the outbred offspring, as compared to the more stable environment when transmitted to selfed offspring. To quantify the fitness consequences of this 14% prevalence difference, we studied the within-season epidemiology of O. bayeri, using an epidemiological model. We then examined whether descendants of outbred offspring produce more resting eggs than the descendants of selfed offspring. The data and our model show that Daphnia which are uninfected at the beginning of the growth season have a large advantage when the entire season is considered. Our data support the Red Queen hypothesis which states that in the presence of coevolving parasites, outbreeding is favoured in the host.
Faculties and Departments:05 Faculty of Science > Departement Umweltwissenschaften > Integrative Biologie > Evolutionary Biology (Ebert)
UniBasel Contributors:Ebert, Dieter
Item Type:Article, refereed
Article Subtype:Research Article
Publisher:The Royal Society
Note:Publication type according to Uni Basel Research Database: Journal article
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Last Modified:22 Jun 2021 10:04
Deposited On:22 Jun 2021 10:04

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