Prey around the world experience the risk of predation, and most have evolved constitutive and phenotypically plastic defences in response. Phenotypically plastic defences often come with trade-offs related to foraging, such that the magnitude of defence is mediated by body condition and food availability. Such adaptive responses are beneficial to prey, and there is an increasing appreciation that they can be disrupted by chemical compounds resulting from human activities. We examined predator-induced behaviours in freshwater snails (Physa acuta) using 32 combinations of different concentrations of olfactory predator cues, body condition and food availability to understand how they respond to the trade-off between avoiding predators and obtaining food. Using a subset of these conditions (16 environments), we then examined how snail responses were altered by increases or decreases in pH. We found that snails responded to increased predator cue concentrations with a shape consistent with a saturating response curve and that low body condition and low food availability weakened these responses. When we increased pH (from 7.8 to 9.5), snails exhibited weaker predator avoidance responses, but only in the absence of food. When we decreased pH (from 7.8 to 6.0), snails exhibited stronger predator avoidance responses and stronger declines in foraging, but only in the presence of food. Collectively, these results suggest that changes in pH due to acid mine drainage, eutrophication and ocean acidification may substantially alter the adaptive responses of aquatic animals. Future work should determine whether such info-disruption is common in other taxa, determine the underlying mechanisms and quantify the consequences of info-disruption to predator–prey and prey–resource interactions.

中文翻译：

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捕食者行为受猎物状况、食物供应和 pH 值介导的信息中断影响

世界各地的猎物都面临着被捕食的风险，大多数猎物已经进化出组成型和表型可塑性防御作为回应。表型塑料防御通常伴随着与觅食相关的权衡，因此防御的程度取决于身体状况和食物供应情况。这种适应性反应有利于猎物，人们越来越意识到它们可能会被人类活动产生的化合物破坏。我们使用 32 种不同浓度的嗅觉捕食者线索、身体状况和食物供应情况的组合，研究了淡水蜗牛 (Physa acuta) 中捕食者诱发的行为，以了解它们如何应对避免捕食者和获取食物之间的权衡。使用这些条件的一个子集（16 个环境），然后，我们研究了 pH 值的升高或降低如何改变蜗牛的反应。我们发现蜗牛以与饱和反应曲线一致的形状对增加的捕食者线索浓度作出反应，而低身体状况和低食物供应削弱了这些反应。当我们增加 pH 值（从 7.8 到 9.5）时，蜗牛表现出较弱的捕食者回避反应，但仅在没有食物的情况下。当我们降低 pH 值（从 7.8 到 6.0）时，蜗牛表现出更强的躲避捕食者反应和更强烈的觅食下降，但仅在有食物的情况下。总的来说，这些结果表明，由于酸性矿山排水、富营养化和海洋酸化导致的 pH 值变化可能会显着改变水生动物的适应性反应。未来的工作应该确定这种信息中断是否在其他分类群中很常见，