Data from: 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 faster under predation risk compared to the no-predator treatment, an effect that stemmed from a disproportionate, negative effect of predation risk on the post-hatching survival instead of hatching rate. We discuss our results in terms of a hypothesized consequence of elevated stress hormone levels.繁殖表现通常具有年龄依赖性，在整个生命周期中呈现出性能提升与衰老的动态变化模式，同时还会与其他性状存在生活史权衡。已有研究表明，高水平的外源性死亡（例如由捕食者引发的死亡）有时会在自然与实验室环境中，通过自然选择促使衰老进程加速，但该效应并非普遍存在。本研究探究了捕食风险（即非致命性暴露于捕食者的化学信号中）对静水椎实螺（*Physa acuta*）繁殖成功率的诱导（即表型可塑性）效应。实验采用2×2因子设计：将淡水螺分别置于有捕食性螯虾化学信号与无该信号的环境中饲养，并设置早期交配与晚期交配两组处理；随后测定其后代的卵孵化率及孵化后早期存活率。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幼体的早期存活产生跨代效应。此外，相较于无捕食者的对照组，捕食风险组的繁殖成功率下降速率快3倍以上，该效应源于捕食风险对孵化后存活率产生了不成比例的负面影响，而非对孵化率的作用。本研究结合应激激素水平升高的相关假说，对实验结果展开了讨论。