Prey seldom rely on a single type of antipredator defence, often using multiple defences to avoid predation. In many cases, selection in different contexts may favour the evolution of multiple defences in a prey. However, a prey may use multiple defences to protect itself during a single predator encounter. Such "defence portfolios" that defend prey against a single instance of predation are distributed across and within successive stages of the predation sequence (encounter, detection, identification, approach (attack), subjugation and consumption). We contend that at present, our understanding of defence portfolio evolution is incomplete, and seen from the fragmentary perspective of specific sensory systems (e.g., visual) or specific types of defences (especially aposematism). In this review, we aim to build a comprehensive framework for conceptualizing the evolution of multiple prey defences, beginning with hypotheses for the evolution of multiple defences in general, and defence portfolios in particular. We then examine idealized models of resource trade-offs and functional interactions between traits, along with evidence supporting them. We find that defence portfolios are constrained by resource allocation to other aspects of life history, as well as functional incompatibilities between different defences. We also find that selection is likely to favour combinations of defences that have synergistic effects on predator behaviour and prey survival. Next, we examine specific aspects of prey ecology, genetics and development, and predator cognition that modify the predictions of current hypotheses or introduce competing hypotheses. We outline schema for gathering data on the distribution of prey defences across species and geography, determining how multiple defences are produced, and testing the proximate mechanisms by which multiple prey defences impact predator behaviour. Adopting these approaches will strengthen our understanding of multiple defensive strategies.

中文翻译：

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多种反捕食者防御的进化和生态。

猎物很少依赖单一类型的反捕食者防御，通常使用多种防御来避免捕食。在许多情况下，不同环境下的选择可能有利于猎物多重防御的进化。然而，在一次捕食者遭遇中，猎物可能会使用多重防御来保护自己。这种保护猎物免受单一捕食实例的“防御组合”分布在捕食序列的连续阶段（遭遇、检测、识别、接近（攻击）、征服和消耗）中。我们认为，目前我们对防御组合演变的理解是不完整的，并且是从特定感觉系统（例如视觉）或特定类型的防御（尤其是警戒系统）的碎片角度来看的。在这篇评论中，我们的目标是建立一个全面的框架来概念化多重猎物防御的演变，首先是对一般多重防御，特别是防御组合的演变的假设。然后，我们研究资源权衡和特征之间功能相互作用的理想化模型，以及支持它们的证据。我们发现，防御组合受到生命史其他方面的资源分配以及不同防御之间功能不兼容的限制。我们还发现，选择可能有利于对捕食者行为和猎物生存产生协同效应的防御组合。接下来，我们研究猎物生态、遗传学和发育以及捕食者认知的具体方面，这些方面修改了当前假设的预测或引入了竞争假设。我们概述了收集有关跨物种和地理区域的猎物防御分布数据的方案，确定如何产生多种防御，并测试多种猎物防御影响捕食者行为的直接机制。采用这些方法将加强我们对多种防御策略的理解。