Breed early, breed late? Molecular, neuroendocrine, and developmental mechanisms regulating timing of reproduction

变化在本质上是不变的，而且一直是不变的。物种生存、扩展或灭绝的可能性取决于它们利用环境信息准确计时生活史转变的能力。为了成功，物种需要在一年中有利于饲养后代的时间进行繁殖。在一个快速变化的环境中，决定动物何时繁殖的机制的灵活性水平将在确定种群水平的复原力方面发挥关键作用。这项研究将使用尖端技术和实验方法来确定决定动物何时繁殖的机制(分子、神经内分泌和发育)。此外，为了了解决定动物何时在不断变化的环境中繁殖的机制，该项目还将提供教育和推广机会，让社区参与到当地到全球范围内的候鸟保护工作中。在生态进化背景下整合机制和功能的研究为理解生物系统变化的方向和动态提供了巨大的希望。这项研究将综合导致种群内和种群间生殖发育时间差异的机制。将提供对季节性、神经内分泌学和表型灵活性领域的基本见解。这项研究将利用黑眼麻雀(Junco Hyemalis)密切相关的季节性同域种群在繁殖时机上的显著差异。JUNCO是一种由一系列迁徙种群和居住种群组成的物种，当它们暴露在相同的环境线索(如日长、温度)时，它们在冬季和早春共存。尽管在冬季和早春暴露在相同的环境线索下，一些种群会推迟繁殖来迁徙，而另一些种群则不会。这个项目将使用季节性共生的丛林来1)通过确定基因表达和基因序列变异的相对重要性，更深入地理解遗传和表观遗传变异是如何转化为生殖时机的表型变异的。2)检验这一假设，即与传统的计时模型相反，生殖轴的动态反馈在计时再生产中起着关键作用。3)从实验上检验这一假设，即在发育过程中经历的日长决定了成年人开始生殖的日长。此外，为了了解决定JUNCO物种迁徙和繁殖时机的机制，该项目还将提供教育和外联机会，通过让项目受训者与公民科学家接触，在当地到全球范围内让社区参与保护候鸟。教育和外展机会将在实地完成，并通过与当地学校的既定外展活动来实现。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Change is and always has been constant in nature. The likelihood that species will persist, expand, or go extinct depends on their ability to employ environmental information to accurately time life-history transitions. To succeed, species need to reproduce at times of the year that are favorable for rearing offspring. In a rapidly changing environment, the level of flexibility in the mechanisms that determine when animals reproduce will play a critical role in determining population-level resilience. The research will employ cutting edge technology and experimental approaches to identify the mechanisms (molecular, neuroendocrine, and developmental) that determine when animals breed. In addition, to understanding the mechanisms that determine when animals breed in changing environments, the project will also provide education and outreach opportunities to engage communities in the conservation of migratory birds on a local to global scale.Research that integrates mechanism and function in eco-evolutionary contexts holds great promise for understanding the direction and dynamics of change in living systems. The research will synthesize the mechanisms that lead to within- and among-population differences in the timing of reproductive development. Basic insights will be provided to the fields of seasonality, neuroendocrinology, and phenotypic flexibility. The research will make use of striking differences in timing of reproduction in closely related, seasonally sympatric populations of a sparrow, the dark-eyed junco (Junco hyemalis). The junco is a species that consists of an array of migratory and resident populations known to co-occur during winter and early spring when they are exposed to the same environmental cues (e.g., day length, temperature). Despite exposure to the same environmental cues in winter and early spring, some populations delay reproduction to migrate, while others do not. This project will use seasonally sympatric juncos to 1) Achieve a deeper understanding of how genetic and epigenetic variation are translated into phenotypic variation in reproductive timing by determining the relative importance of variation in gene expression and gene sequences. 2) Test the hypothesis that, contrary to traditional models of timing, dynamic feedback from the reproductive axis plays a critical role in timing reproduction. 3) Test experimentally the hypothesis that day length experienced during development sets the day length at which reproduction begins in adults. In addition, to understanding the mechanisms that determine the migratory and reproductive timing of junco species, the project will also provide education and outreach opportunities to engage communities in the conservation of migratory birds on a local to global scale, by engaging the trainees on the project with citizen scientists. The education and outreach opportunities will be accomplished in the field and via established outreach activities with local schools.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.