Predator–prey interactions are crucial components of populations and communities. Their dynamics depend on the covariation of traits of the interacting organisms, and there is increasing evidence that intraspecific trade‐off relationships between defense and competitive traits are important drivers of trophic interactions. However, quantifying the relevant traits forming defense–competitiveness trade‐offs and how these traits determine prey and predator fitness remains a major challenge. Here, we conducted feeding and growth experiments to assess multiple traits related to defense and competitiveness in six different strains of the green alga Chlamydomonas reinhardtii exposed to predation by the rotifer Brachionus calyciflorus. We found large differences in defense and competitive traits among prey strains and negative relationships between these traits for multiple trait combinations. Because we compared trait differences among strains whose ancestors evolved previously in controlled environments where selection favored either defense or competitiveness, these negative correlations suggest the presence of a trade‐off between defense and competitiveness. These differences in traits and trade‐offs translated into differences in prey and predator fitness, demonstrating the importance of intraspecific trade‐offs in predicting the outcome of predator–prey interactions.

中文翻译：

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浮游生物捕食者-猎物系统中防御和竞争特征之间的权衡


捕食者与猎物的互动是种群和群落的重要组成部分。它们的动力学取决于相互作用生物体性状的协变，并且越来越多的证据表明防御和竞争性状之间的种内权衡关系是营养相互作用的重要驱动因素。然而，量化形成防御-竞争力权衡的相关特征以及这些特征如何决定猎物和捕食者的适应性仍然是一个重大挑战。在这里，我们进行了摄食和生长实验，以评估六种不同绿藻菌株中与防御和竞争力相关的多种性状 莱茵衣藻 暴露于轮虫 Brachionus calyciflorus 的捕食。我们发现猎物品系之间的防御和竞争性状存在很大差异，而对于多个性状组合，这些性状之间存在负相关关系。因为我们比较了其祖先之前在选择有利于防御或竞争力的受控环境中进化的菌株之间的性状差异，所以这些负相关性表明防御和竞争力之间存在权衡。这些性状和权衡的差异转化为猎物和捕食者适应性的差异，证明了种内权衡在预测捕食者-猎物相互作用结果方面的重要性。