Present address: Amy C. Krist, Department of Biology, Phillips Hall 330, University of Wisconsin – Eau Claire, Eau Claire, WI 54701, USA.
Genotypic vs. condition effects on parasite-driven rare advantage
Version of Record online: 23 JUN 2004
Journal of Evolutionary Biology
Volume 17, Issue 5, pages 967–973, September 2004
How to Cite
Dybdahl, M. F. and Krist, A. C. (2004), Genotypic vs. condition effects on parasite-driven rare advantage. Journal of Evolutionary Biology, 17: 967–973. doi: 10.1111/j.1420-9101.2004.00759.x
- Issue online: 23 JUN 2004
- Version of Record online: 23 JUN 2004
- Received 23 January 2004; revised 1 April 2004; accepted 5 April 2004
- frequency-dependent selection;
- host–parasite interactions;
- parasite resistance;
- Red Queen hypothesis;
Models and empirical studies of coevolution assume host resistance and parasite infectivity are genetically based. However, nongenetic physiological or environmental influences could alter host susceptibility even when the relationship is genetically based. In this experiment we examined the influence of host genotype, host condition at the time of infection (age and reproductive status), and their interaction on resistance of the freshwater snail Potamopyrgus antipodarum) to its dominant trematode parasite (Microphallus sp.). We used a laboratory infection experiment of a clonal snail population to determine the susceptibility of juveniles, brooding adult females, and nonbrooding adult females. We found a significant effect of both life-history state and clonal genotype on the prevalence of infection. However, the relative susceptibility of different clonal genotypes was not altered by condition; genotypes that were rare in the natural population were less infected than those that were common for each life-history state. These results suggest that although host condition affects susceptibility, it does not disrupt the specificity of the match between parasites and common clonal genotypes. Hence these findings support the Red Queen hypothesis for the maintenance of sex under genetically based host–parasite interactions.