Predators shape the phenotype of prey by means of local adaptation, within-generation plasticity, and transgenerational plasticity. Theory predicts that the influence of these three mechanisms on phenotype is determined by the number of generations exposed to the predator and the autocorrelation between parent and offspring predator environments. To test theoretical predictions about the relative effects of local adaptation, within-generation plasticity, and transgenerational plasticity on prey phenotype, we exposed two generations of freshwater snails (Physa acuta) from two populations—one from a large pond containing predatory fish and one from a set of small ponds that lacked predatory fish—to the cues from a predaceous bluegill sunfish (Lepomis macrochirus). Physa acuta exhibit both local adaptation and phenotypic plasticity in response to predation risk; thus, we predicted that snails from the population with fish and snails experimentally exposed to fish cues would produce more globose (or spherical), crush-resistant shells. In addition, given the prolonged exposure to fish predation, we predicted that snails from the population with fish would exhibit reduced phenotypic plasticity. We found evidence that snails from the population with fish were generally more globose and more crush resistant than snails from the fish-less population and exposure to fish cues led snails from both populations to develop more globose shells with increased crush resistance. However, contrary to our predictions, the offspring of snails from both populations exposed to fish cues had elongated shells and reduced crush resistance. This may reflect the negative effects of parental stress or variation in resource investment.

中文翻译：

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淡水蜗牛对鱼类捕食的反应整合了表型可塑性和局部适应性

捕食者通过局部适应，代内可塑性和跨代可塑性来塑造猎物的表型。理论预测，这三种机制对表型的影响取决于暴露于捕食者的世代数以及父母与后代捕食者环境之间的自相关。为了测试有关局部适应性，世代可塑性和跨代可塑性对猎物表型的相对影响的理论预测，我们暴露了两个种群的两代淡水蜗牛（Physa acuta），一个种群来自一个装有掠食性鱼类的大池塘，另一个种群来自捕食性鱼类。一组缺少掠食性鱼类的小池塘，这些捕捞池来自早先的蓝blue翻车鱼（Lepomis macrochirus）的线索。番茄对捕食风险表现出局部适应性和表型可塑性；因此，我们预测鱼类中的蜗牛和实验性地暴露于鱼线索的蜗牛会产生更多的球形（或球形），抗压壳。此外，鉴于长时间暴露于鱼类的捕食中，我们预测来自鱼类种群的蜗牛表现出降低的表型可塑性。我们发现有证据表明，有鱼种群的蜗牛通常比无鱼种群的蜗牛更球形和更耐压，暴露于鱼线索下使这两个种群的蜗牛都发展出更多的球形外壳，增加了抗压性。但是，与我们的预测相反，这两种种群的蜗牛的后代都受到鱼鳞的影响，它们的壳变长，抗压碎性降低。