Understanding the diversity of anti-predator defence

了解反捕食者防御的多样性

• 批准号: RGPIN-2014-04661
• 负责人: Sherratt, Thomas
• 金额: $ 3.64万
• 依托单位: Carleton University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=631953
• 关键词: Understanding; diversity; anti; predator; defence

INTRODUCTION: Go into most Canadian backyards and you are likely to see numerous examples of protective colour patterns: moths that resemble their backgrounds, warningly-coloured ladybugs, and harmless hover flies that gain protection by resembling stinging wasps or bees. Over the last century, researchers have come to understand precisely how these defensive traits serve to protect organisms from predators. However, in treating each of these defensive adaptations independently, more fundamental questions have been overlooked. In particular, why have some species evolved one form of defence, while other species have evolved another? Likewise, why have some mimetic species evolved an almost perfect resemblance to their aversive models, while other species have evolved only a crude similarity? Over the course of this research program, I propose to test a series of key hypotheses which will help us understand why species evolve the defences that they do. Each of these hypotheses arises directly from an appreciation that anti-predator defences are the outcome of co-evolution between predators and prey, and therefore depend on a fundamental understanding of not just prey life history, but also predator cognition. OBJECTIVES: I have three objectives. First, I shall characterize observed variation in defences, ranging from eyespots in caterpillars to mimicry in hover flies, within a phylogenetic framework. From here, I will test for predicted associations between the evolved mode of defence and other attributes such as body size, and phenology. Many of the predicted associations arise directly from untested assumptions as to how predators would react to a given defence. Therefore, my second objective will be to test specific hypotheses as to how predator behaviour shapes the observed variation in prey defence. Third, in seeking fundamental explanations for the observed predator behaviours, I will develop and evaluate adaptive explanations for established psychological phenomena that have hitherto been considered primarily at the proximate level.METHODS: I will utilise phylogenetic reconstruction of past events to elucidate evolutionary patterns, and to characterise transitions between different defensive strategies, such as the trait changes necessary for wasp mimicry to evolve into bee mimicry. I will support these analyses by investigating the nature of predator behaviour proposed to generate this diversity. For example, I will use field trials to quantify the selective advantage of eyespots in different types of caterpillar by monitoring the survivorship of artificial caterpillars of different size, and I will evaluate how and why wild birds tend to overlook potentially informative features when discriminating palatable from unpalatable prey. To complement this work, I will develop original optimization models to evaluate whether any of the observed behaviours (such as a fear of novel cues and the use of a restricted set of discriminative features) can be understood from an adaptive perspective.SIGNIFICANCE: Predation is one of the most universal and important agents of selection, responsible for a bewildering array of traits in the natural world. Here we will test clear hypotheses as to why different species have evolved different anti-predator defences, and examine the role of predator cognition in shaping these defences. After decades of research in which camouflage, warning signals and mimicry were viewed independently, here we adopt a far broader perspective aimed at understanding how adaptive predator behaviour and cognition shape the diversity of anti-predator traits in prey.

简介：走进大多数加拿大后院，您可能会看到许多保护性颜色图案的例子：与背景相似的飞蛾、带有警告色的瓢虫，以及通过类似于带刺的黄蜂或蜜蜂获得保护的无害的悬停蝇。在上个世纪，研究人员已经开始准确地了解这些防御特征如何保护生物体免受捕食者的侵害。然而，在独立对待这些防御性适应时，更基本的问题被忽视了。特别是，为什么有些物种进化出了一种防御形式，而其他物种则进化出了另一种防御形式？同样，为什么一些模仿物种进化出了与其厌恶模型几乎完美的相似性，而其他物种却进化出了粗略的相似性？在这个研究计划的过程中，我建议测试一系列关键假设，这将有助于我们理解为什么物种会进化出它们所具有的防御能力。这些假设中的每一个都直接源于这样一种认识，即反捕食者防御是捕食者和猎物之间共同进化的结果，因此不仅取决于对猎物生活史的基本理解，还取决于对捕食者认知的基本理解。目标：我有三个目标。首先，我将在系统发育框架内描述观察到的防御变异，从毛毛虫的眼斑到悬停蝇的拟态。从这里开始，我将测试进化的防御模式与其他属性（例如体型和物候学）之间的预测关联。许多预测的关联直接源自未经检验的假设，即捕食者将如何对给定的防御做出反应。因此，我的第二个目标是测试关于捕食者行为如何影响观察到的猎物防御变化的具体假设。第三，在寻求对观察到的捕食者行为的基本解释时，我将开发和评估对迄今为止主要在近似水平上考虑的既定心理现象的适应性解释。方法：我将利用过去事件的系统发育重建来阐明进化模式，并描述不同防御策略之间的转变，例如黄蜂拟态所需的性状变化 进化成蜜蜂模仿。我将通过调查旨在产生这种多样性的捕食者行为的本质来支持这些分析。例如，我将使用现场试验，通过监测不同大小的人工毛毛虫的存活率来量化不同类型毛毛虫眼斑的选择性优势，并且我将评估野生鸟类在区分可口与不可口猎物时如何以及为何倾向于忽略潜在的信息特征。为了补充这项工作，我将开发原始的优化模型来评估是否可以从适应性的角度理解任何观察到的行为（例如对新线索的恐惧和使用一组有限的区分性特征）。 意义：捕食是最普遍和最重要的选择因素之一，导致了自然世界中一系列令人眼花缭乱的特征。在这里，我们将测试关于为什么不同物种进化出不同的反捕食者防御的明确假设，并研究捕食者认知在形成这些防御中的作用。经过数十年对伪装、警告信号和模仿进行独立观察的研究，我们在这里采用了更广泛的视角，旨在了解适应性捕食者行为和认知如何塑造猎物反捕食者特征的多样性。