Dissertation Research: Physiological Mediation of an Age-related Life History Trade-off

预计成年人会随着年龄的增长而增加生殖投资。 这被认为是因为随着成年人年龄的增长，他们未来的生殖尝试必然会减少。 一些研究支持这一预期，然而，我们目前几乎没有关于介导这种常见模式的生理机制的信息。 在调节父母投资中与年龄相关的变化中可能重要的一种生理机制是应激反应的减弱和对糖皮质激素水平升高的敏感性降低。 脊椎动物对压力的反应是释放糖皮质激素。 糖皮质激素水平升高会抑制生殖行为并增强自我维持行为。 因此，预计成年人会抑制应激反应，并且随着年龄的增长，对升高的糖皮质激素水平的行为敏感性降低。 本研究将探讨是否在应激反应和糖皮质激素敏感性的变化介导的年龄相关的变化，父母的投资在长寿的海鸟，常见的燕鸥。 这项研究将提高我们对压力生理学和年龄之间的关系的理解，以及我们对介导与年龄相关的生活史权衡的生理机制的理解。更广泛的影响：本科研究人员将参与本研究项目的各个方面。 此外，这项研究可能具有重要的保护意义。 关于年龄如何影响压力反应的知识可能会告知野生动物管理人员哪些群体最容易受到环境干扰的影响。

Adults are predicted to increase reproductive investment with age. This is thought to occur because as adults age, they necessarily have fewer future reproductive attempts. Several studies support this expectation, however, we currently have little information about the physiological mechanisms mediating this commonly observed pattern. One physiological mechanism that may be important in regulating age-related changes in parental investment is the attenuation of the stress response and decreased sensitivity to elevated glucocorticoid levels. In response to stress, vertebrates release glucocorticoids. Elevated glucocorticoid levels inhibit reproductive behaviors and enhance self-maintenance behaviors. Therefore, adults are predicted to suppress the stress response and to be less behaviorally sensitive to elevated glucocorticoid levels with age. This study will investigate whether changes in the stress response and glucocorticoid sensitivity mediate age-related changes in parental investment in a long-lived seabird, the common tern Sterna hirundo. This research will enhance our understanding of the relationship between stress physiology and age as well as our understanding of the physiological mechanisms mediating age-related life-history trade-offs.Broader Impacts: Undergraduate researchers will be involved in all aspects of this research project. In addition, this research may have important conservation implications. Knowledge about how age influences the stress response may inform wildlife managers about which segments of the population are the most vulnerable to environmental disturbance.