Parasite-mediated selection in experimental Daphnia magna populations
Parasite-mediated selection in experimental Daphnia magna populations
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DOI：
10.1111/j.0014-3820.2003.tb00260.x
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发表时间：
2003-02-01
期刊：
影响因子：
3.3
通讯作者：
Ebert, D
中科院分区：
文献类型：
--
作者：
Capaul, M;Ebert, D
已有研究表明，寄生虫对寄主具有很强的选择能力，因此可能改变不同寄主类型之间的竞争结果。我们测试了不同寄生虫种类的寄生虫介导的选择在多大程度上影响了循环孤雌生殖的克隆之间的竞争。我们监测了由21个D.Magna克隆组成的实验室微宇宙种群中克隆频率的变化。寄生虫处理(两种微孢子虫，肠小球虫和胶状奥多斯孢子虫)和无寄生虫对照处理被跟踪超过9个月。用分枝巴氏杆菌进一步治疗失败了。我们发现不同处理之间的克隆成功率有显著差异：两个寄生虫处理与对照处理不同，也不同于彼此。此外，我们还测量了受感染和未受感染雌性的克隆特定种群承载能力、与测试者克隆的竞争能力以及繁殖成功，以测试它们是否与微观世界中的克隆成功相关。在微观世界中，克隆特异性竞争能力是克隆成功的良好预测因子，但克隆载量和寄主繁殖成功不能预测克隆成功。我们的研究表明，寄生虫介导的选择可以强烈地改变克隆竞争的结果。这些结果表明，寄生虫可能会影响大型水蚤种群在无性繁殖期间的微进化。
It has been suggested that parasites are a strong selecting force for their hosts and therefore may alter the outcome of competition among host genotypes. We tested the extent to which parasite-mediated selection by different parasite species influenced competition among clones of the cyclic parthenogen Daphnia magna. We monitored clone frequency changes in laboratory microcosm populations consisting of 21 D. magna clones. Parasite treatments (two microsporidians, Glugoides intestinalis and Ordospora colligata) and a parasite-free control treatment were followed over a nine-month period. A further treatment with the bacterium Pasteuria ramosa failed. We found significant differences in clonal success among the treatments: the two parasite treatments differed from the control treatment and from each other. Additionally, we measured the clone-specific population carrying capacity, competitive ability against tester clones, and reproductive success of infected and uninfected females to test whether they correlate with clonal success in the microcosms. The clone-specific competitive ability was a good predictor of clonal success in the microcosms, but clonal carrying capacity and host reproductive success were not. Our study shows that parasite-mediated selection can strongly alter the outcome of clonal competition. The results suggest that parasites may influence microevolution in Daphnia populations during periods of asexual reproduction.