Physiological Responses to Predators and Their Consequences for the Growth/Predation Risk trade-off

许多生物通过改变生理、行为和形态来应对捕食者的威胁。这些减少被捕食者杀死的可能性的尝试，往往是以减少生长为代价的。尽管从细菌到植物和动物的生物体都表现出这种反应，但人们对这种权衡的潜在原因知之甚少。在捕食者存在的情况下，生长速度下降可能部分是由于减少摄食的行为反应，但生理变化也可能起主要作用。本研究将探讨不同种类和属的豆娘幼虫对捕食者的生理反应差异，以及这些差异对代谢资源分配和行为的影响，以及这些特征的进化。将进行五项研究，以检查物种的生理反应和摄入资源在体内各种分子的分配。第一项研究将对12个物种进行调查，以测量生物体内的自然生长速度和葡萄糖、糖原、甘油三酯和蛋白质的含量。第二个实验将通过实验确定在捕食者存在和实验室食物供应的处理下这些分子的生长和分配的变化。三是实地试验，检验室内对照试验所得结果在真实湖泊中是否得到证实。第四部分检验了诱导生理反应的属之间的近似差异的假设。最后，第五章考察了这种对捕食者的生理反应的更广泛的进化历史。这项工作探讨了两组昆虫之间生态表现根本差异的生理机制。这对于理解个体的表型如何塑造其与环境和其他物种相互作用的能力至关重要。此外，研究这种生理学是如何进化的，为物种如何适应各种环境以及自然和人为引起的环境变化（例如，自然栖息地转移，气候变化，栖息地退化）提供了有价值的见解。

Many organisms respond to the threat of predators by altering their physiology, behavior and morphology. These attempts to reduce their likelihood of being killed by a predator, often come at the cost of reducing growth. Although organisms from bacteria to plants and animals show such responses, the underlying reasons for this trade-off are poorly understood. Reduced growth in the presence of predators may result in part from behavioral responses to reduce feeding, but physiological changes also may play a major role. This research will explore the differences among species and genera of larval damselflies (Hexapoda: Odonata) in physiological response to predators, the consequences of these differences for metabolic resource allocation and behavior, and the evolution of these traits. Five studies will be performed to examine the physiological responses of species and the allocation of ingested resources to various molecules in the body. The first study will survey 12 species to measure natural growth rates and the amount of glucose, glycogen, triglycerides and protein in the organism's body. The second will experimentally determine alterations in growth and allocation to these molecules under treatments of predator presence and food availability in the lab. The third is a field experiment to test whether the results obtained in the controlled laboratory experiment are substantiated in real lakes. The fourth tests hypotheses about the proximate differences between the genera that induce the physiological response. Finally, the fifth examines the broader evolutionary history of this physiological response to predators.This work explores the physiological mechanisms underlying a fundamental difference in ecological performance between two groups of insects. This is critical to understanding how an individual's phenotype shapes its ability to engage in interactions with its environment and with other species. Also, examining how this physiology has evolved provides valuable insights into how species adapt to various environments and to natural and anthropogenically-induced environmental change (e.g., natural habitat shifts, climate change, habitat degradation).