Age-dependent effects of predation risk on reproductive success in a freshwater snail

Reproductive performance is often age-dependent, showing patterns of improvement and/or senescence as well as trade-offs with other traits throughout the lifespan. High levels of extrinsic mortality (e.g., from predators) have been shown to sometimes, but not always, select for accelerated actuarial senescence in nature and in the lab. Here we explore the inductive (i.e., plastic) effects of predation risk (i.e., non-lethal exposure to chemical cues from predators) on the reproductive success of freshwater snails (Physa acuta). Snails were reared either in the presence or absence of chemical cues from predatory crayfish and mated early in life or late in life (a 2×2 factorial design); we measured egg hatching and early post-hatching survival of their offspring. Both age and predation risk reduced reproductive success, illustrating that predation risk can have a cross-generational effect on the early survival of juveniles. Further, the decline in reproductive success was over 3 times fas...

繁殖表现通常具有年龄依赖性，在整个生命周期中会呈现出性能提升和/或衰老的模式，同时还会与其他性状存在进化权衡。已有研究证实，高水平的外源性死亡（例如由捕食者引发的死亡）有时会，但并非始终，在自然环境与实验室环境中促使自然选择倾向于加速的统计性衰老（actuarial senescence）。本研究旨在探究捕食风险（即非致命性暴露于捕食者的化学信号）对淡水蜗牛（Physa acuta）繁殖成功率的诱导（即可塑性）效应。研究采用2×2因子实验设计：将淡水蜗牛分别置于有捕食性螯虾化学信号、无捕食性螯虾化学信号的环境中饲养，并让其在生命早期或晚期进行交配；随后我们测定了其后代的卵孵化率以及孵化早期存活率。年龄与捕食风险均会降低繁殖成功率，这表明捕食风险可对子代幼体的早期存活产生跨代效应。进一步而言，繁殖成功率的下降幅度超过3倍[原文内容未完整显示]