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

变化一直是自然界的常态。物种延续、扩张或灭绝的可能性取决于它们利用环境信息准确把握生活史转变时间的能力。为了成功，物种需要在一年中适合养育后代的时间繁殖。在快速变化的环境中，决定动物何时繁殖的机制的灵活性水平将在决定种群水平的恢复力方面发挥关键作用。这项研究将采用尖端技术和实验方法来确定动物繁殖的机制（分子、神经内分泌和发育）。此外，为了了解动物在不断变化的环境中何时繁殖的机制，该项目还将提供教育和推广机会，让社区参与到当地乃至全球范围内的候鸟保护中来。在生态进化背景下整合机制和功能的研究对于理解生命系统变化的方向和动力具有很大的希望。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。基本的见解将提供给季节性，神经内分泌学和表型灵活性领域。这项研究将利用一种密切相关的、季节性同属的麻雀种群——黑眼junco （junco hyemalis）——在繁殖时间上的显著差异。junco是一种由一系列迁徙种群和常住种群组成的物种，当它们暴露于相同的环境线索（例如，白天的长度，温度）时，它们会在冬季和早春同时出现。尽管在冬季和早春暴露在相同的环境条件下，一些种群推迟繁殖以迁移，而另一些种群则不会。该项目将利用季节性同域juncos， 1)通过确定基因表达和基因序列变异的相对重要性，更深入地了解遗传和表观遗传变异如何转化为生殖时间的表型变异。2)验证与传统定时模型相反的假设，即来自生殖轴的动态反馈在定时繁殖中起着关键作用。3)通过实验验证这样一个假设，即发育期间经历的日照长度决定了成年动物开始繁殖的日照长度。此外，为了了解决定junco物种迁徙和繁殖时间的机制，该项目还将通过让项目学员与公民科学家一起参与项目，为社区提供教育和推广机会，以参与当地到全球范围内的候鸟保护。教育和外联机会将在实地完成，并通过与当地学校的既定外联活动来完成。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值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.