Mediation of optimal reproductive decisions by maternal stress

种群和生态系统的健康是由个体在不断变化的环境条件下最大化其适应性的能力所驱动的。由于生理功能直接介导了生物体与其环境的关系，因此生理特征作为生活史决策和权衡的调节器，可以用来研究塑造适应性变化的生理特征。然而，尽管许多理论工作预测了生理与生态或环境过程之间的预期关系，但许多生理性状未能表现出一致的个体水平变化，不能普遍适用于不同的分类群，或者难以在野生系统中进行实验操作。类固醇激素现在被认为在复杂性状的适应和进化中起关键作用。“压力”激素的基线水平是调节个体内部和个体之间投资决策的绝佳候选者，因为它们调节着脊椎动物日常和季节性的能量平衡。尽管最近的工作集中在试图将压力激素与健康直接联系起来，但这些研究往往发现模棱两可的结果。很少有研究旨在解释基线应激激素和健康之间更复杂，但可能更具生物学相关性的联系。本申请中概述的研究计划和相关项目旨在回答一些基本的，但目前还缺失的问题。我特别要测试基线应激激素是否：I)整合个体和环境的可变性，ii)为能量昂贵的生活史阶段的表现需求做好准备，iii)调节适应性投资决策，从而调节适应性，以及iv)通过生态和生活史水平背景调节它们的权衡和适应性效应。这种类型的机械信息不仅对基础的探索性科学研究非常重要，而且在应用研究中也越来越关键和需要，以提高我们对在北极等敏感生态系统中繁殖的个体和种群在面对越来越多的人为压力源时如何公平和应对的预测能力

Population and ecosystem health are driven by the capacity of individuals to maximize their fitness under continuously changing environmental conditions. Since physiological function directly mediates the relationship of the organism to its environment, physiological traits are useful to study as regulators of the life-history decisions and trade-offs that shape variation in fitness. However, despite much theoretical work predicting expected relationships between physiology and ecological or environmental processes, many physiological traits fail to show consistent individual-level variation, cannot be universally applied across diverse taxa, or are hard to experimentally manipulate in wild systems. Steroid hormones are now recognized to be critically involved in the adaptation and evolution of complex traits. Baseline levels of `stress' hormones are fantastic candidates for mediating investment decisions both within and among individuals since they regulate daily and seasonal energetic balance in vertebrates. Although recent work has focused on trying to link stress hormones directly to fitness, these studies often find equivocal results. Very few studies are designed to interpret more complex, but likely more biologically relevant, linkages between baseline stress hormones and fitness. The research program and associated projects outlined in this application are designed to answer some of these fundamental, and yet currently missing, questions. I am specifically going to test whether baseline stress hormones: i) integrate individual and environmental variability, ii) prepare individuals for the performance demands of energetically expensive life-history stages, iii) mediate adaptive investment decisions, and therefore fitness, and iv) modulate their trade-off and fitness effects via ecological and life-history level contexts. This type of mechanistic information is not only very important for basic exploratory scientific studies, but it is increasingly key and needed in applied research to increase the predictive power of how we expect individuals and populations breeding in sensitive ecosystems like the Arctic to fair and respond as they face increasingly numbers of human-induced stressors.**