Trait-mediated effects of ants on arthropods: From individuals to communities

特质中介效应(TME)是捕食者引起的猎物表型变化，将捕食风险降至最低。虽然TME对捕食者-猎物相互作用的影响可能比捕食更强烈，但我们对它们在构建群落中的作用的了解仍然有限。这是由于对公会内相互作用和陆地系统中的TME研究的显著缺乏，对孤立的物种对而不是多物种相互作用的压倒一切的关注，以及对涉及的化学机制的普遍忽视。该项目的目的是弥合这一生态研究基础领域的三个重要空白。在第一个目标中，我们将利用蚂蚁线索进行行为试验，记录蚂蚁TME在各种蜘蛛物种中的发生，以确定具有强烈反捕食者行为的物种，并测试蜘蛛觅食模式对TME强度的影响。第二个目标集中在TME的化学机制上：不同的蚂蚁化学线索具有不同的衰减率，更多的挥发性信息素指示当前活跃的觅食区域，非挥发性碳氢化合物指示蚂蚁的家园范围。我们将提取不同的蚂蚁线索并对蜘蛛进行行为测试，以确定它们在TME大小中的作用。在第三个目标中，我们将使用最强的TME诱导蚂蚁线索来研究TME的上下文依赖性及其对食物网的间接影响。我们将通过实验评估蜘蛛的食物供应和它们以前的捕食风险经验如何影响蚂蚁TME，以及这种相互作用如何导致节肢动物食物网较低营养水平的级联后果。该提案采取了一种综合的方法，将行为、化学和群落生态学的概念结合在一起，并解决了被忽视的主题，这些主题对于从机械上理解TME在物种相互作用中的作用至关重要。

Trait-mediated effects (TME) are predator-induced changes in prey phenotype that minimize predation risk. While the impact of TME on predator-prey interactions can be stronger than predation, our understanding of their role in structuring communities is still limited. This is due to a striking lack of TME research on intraguild interactions and in terrestrial systems, an overriding focus on isolated species pairs rather on multi-species interactions, and a general disregard for the involved chemical mechanisms. The aim of the project is to close three important gaps in this fundamental area of ecological research.In the first objective, we will perform behavioural trials with ant cues to document the occurrence of ant TME across a wide range of spider species in order to identify species with strong antipredator behavior and to test the influence of spider foraging mode on TME strength. The second objective focuses on the chemical mechanisms of TME: different ant chemical cues have contrasting decay rates, more volatile pheromones signaling currently active foraging areas and non-volatile hydrocarbons indicating ant home range We will extract different ant cues and do behavioural trials with spiders to identify their role in TME magnitude. In the third objective, we will use the strongest TME-inducing ant cue to examine the context-dependence of TME and their indirect effects on the food web. We will experimentally evaluate how ant TME are influenced by food availability to spiders and their previous experience of predation risk, and how this interplay leads to cascading consequences for the lower trophic levels of the arthropod food web. The proposal takes an integrative approach that joins the concepts of behavioural, chemical and community ecology and addresses neglected topics that are crucial to a mechanistic understanding of TME in species interactions.