Parasites of Trinidadian guppies: evidence for sex- and age-specific trait-mediated indirect effects of predators.
Parasites of Trinidadian guppies: evidence for sex- and age-specific trait-mediated indirect effects of predators.
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DOI：
10.1890/14-0495.1
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发表时间：
2015-02
期刊：
影响因子：
4.8
通讯作者：
J. Stephenson;C. van Oosterhout;R. S. Mohammed;J. Cable
中科院分区：
文献类型：
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作者：
J. Stephenson;C. van Oosterhout;R. S. Mohammed;J. Cable
捕食压力可以改变猎物的形态、生理、生活史和行为；其中每一个反过来都会改变幸存的猎物与寄生虫相互作用的方式。这些性状介导的间接影响可能会在生长过程中改变方向或强度，或者在性二态性物种中，在两性之间改变。特立尼达孔雀鱼 Poecilia reticulata 为研究这些相互作用提供了独特的机会；其行为生态学已在具有特征明确的捕食动物群的野生种群中进行了深入研究。众所周知，捕食压力推动了孔雀鱼许多特征的进化。例如，在捕食率高的地区，雌性（而不是雄性）倾向于成群结队，这种反捕食者的行为促进了寄生虫的传播。为了测试自然种群中捕食者驱动的感染差异的证据，我们在 2003 年至 2009 年间从特立尼达岛的 62 个地点收集了 4715 只孔雀鱼，并对它们进行了外共生体筛查，包括环指龙。一项新颖的模型平均分析表明，雌性比雄性更容易感染环指龙寄生虫，但仅限于捕食压力高和感染率高的人群。我们认为，两性之间的成群趋势差异可以解释在高捕食地点观察到的雄性和雌性之间感染率的差异。幼鱼的感染率并不随捕食方式而变化，可能是因为幼鱼面临来自同种成虫的持续捕食压力，因此倾向于在高捕食和低捕食地点成群。这代表了捕食者的年龄和性别特异性特征介导的对其猎物感染概率的间接影响的第一个证据。
Predation pressure can alter the morphology, physiology, life history, and behavior of prey; each of these in turn can change how surviving prey interact with parasites. These trait-mediated indirect effects may change in direction or intensity during growth or, in sexually dimorphic species, between the sexes. The Trinidadian guppy, Poecilia reticulata presents a unique opportunity to examine these interactions; its behavioral ecology has been intensively studied in wild populations with well-characterized predator faunas. Predation pressure is known to have driven the evolution of many guppy traits; for example, in high-predation sites, females (but not males) tend to shoal, and this anti-predator behavior facilitates parasite transmission. To test for evidence of predator-driven differences in infection in natural populations, we collected 4715 guppies from 62 sites across Trinidad between 2003 and 2009 and screened them for ectosymbionts, including Gyrodactylus. A novel model-averaging analysis revealed that females were more likely to be infected with Gyrodactylus parasites than males, but only in populations with both high predation pressure and high infection prevalence. We propose that the difference in shoaling tendency between the sexes could explain the observed difference in infection prevalence between males and females in high-predation sites. The infection rate of juveniles did not vary with predation regime, probably because juveniles face constant predation pressure from conspecific adults and therefore tend to shoal in both high- and low-predation sites. This represents the first evidence for age- and sex-specific trait-mediated indirect effects of predators on the probability of infection in their prey.