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

许多生物通过改变它们的生理、行为和形态来应对捕食者的威胁。 这些试图减少它们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根本原因知之甚少。 在捕食者的存在下，生长的减少可能部分是由于减少进食的行为反应，但生理变化也可能起主要作用。 本研究将探讨豆娘幼虫（六足目：蜻蜓目）种属间对捕食者生理反应的差异，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的资源分配给体内的各种分子。 第一项研究将调查12个物种，以测量自然生长率和生物体内葡萄糖、糖原、甘油三酯和蛋白质的含量。 第二个将在实验室中通过实验确定在捕食者存在和食物可用性的处理下这些分子的生长和分配的变化。 第三个是现场实验，以检验在受控实验室实验中获得的结果是否在真实的湖泊中得到证实。 第四个测试的假设，诱导生理反应的属之间的近似差异。 最后，第五部分探讨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的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生物学引起的环境变化提供了有价值的见解（例如，自然栖息地变化、气候变化、栖息地退化）。

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).