Facing multiple enemies: trade-offs between adaptive responses to predators and parasites in the context of inducible defences.

在自然界中，有机体同时遇到各种敌人，导致在适应性反应之间进行权衡。例如，在捕食者-猎物的相互作用中，针对一个捕食者的防御特征可能会使猎物更容易受到另一个捕食者的攻击。因此，猎物防御特征的表型可塑性是应对不断变化的捕食者光谱的一种广泛的机制。这些诱导防御的成本和收益尚未在同时暴露于不同功能水平的敌人(如捕食者和寄生虫)的背景下进行探索。我们建议研究这种多敌情的影响。具体地说，我们希望解决猎物形态、生活史和行为对捕食者威胁的反应与它们对常见和致命寄生虫的易感性之间的权衡。我们的目标猎物动物(和宿主)将是水蚤(Daphnia)，这是一个在捕食者-猎物和宿主-寄生虫研究中都建立得很好的模型系统，因此将使我们能够建立在早期开发的工具和方法的基础上。这个项目将是捕食者-猎物-寄生虫相互作用的野外采样和实验室实验的结合，并将促进我们对多敌人环境下的适应性可塑性和群落动力学的理解。

In nature, organisms encounter a variety of enemies simultaneously, leading to trade-offs between adaptive responses. In predator-prey interactions, for example, a defence trait against one predator could render the prey more vulnerable to another predator. Hence, phenotypic plasticity in the prey’s defensive traits is a widespread mechanism to cope with a continuously changing predator spectrum. The costs and benefits of these inducible defences have not been explored in the context of simultaneous exposure to enemies from different functional levels, such as predators and parasites. We propose to study the effects of such a multiple-enemy situation. Specifically, we wish to address trade-offs between prey morphological, life-history and behavioural responses to predator threats and their susceptibility to common and virulent parasites. Our target prey animals (and hosts) will be waterfleas (Daphnia), which are a wellestablished model system in both predator-prey and host-parasite research, and will thus allow us to build on earlier developed tools and methods. This project will be a combination of field sampling and laboratory experiments on predator-prey-parasite interactions, and will advance our understanding of adaptive plasticity and community dynamics in a multiple enemy context.