NSF PRFB FY 2023: Thermoregulatory evolution of hummingbirds: Using urban heat islands as a globally replicated natural experiment

该行动资助了美国国家科学基金会2023财年生物学博士后研究奖学金，研究基因组，环境和表型之间相互作用的生命规则的综合研究。该奖学金支持将以创新方式对生活规则领域作出贡献的研究员的研究和培训。由于气候变化，物种面临着环境温度的快速变化。为了生存，生物体需要通过表型变化和基因变化的结合来调整它们的生理机能。这些反应的速度和幅度是否能与不同温度的环境变化相匹配，将决定种群是持续存在还是局部灭绝。这项研究利用城市来研究当代时间尺度上对环境温度变化的进化反应。用铺砌的表面代替植被会产生城市热岛效应，与未受干扰的环境相比，这里的平均温度和极端温度更高。城市热岛效应几乎是世界各地城市的普遍特征，导致了分布均匀、全球复制的热梯度。通过将环境、表型和遗传变异联系起来，研究结果将揭示面对温暖气候的吸热物种的持久性、进化潜力和遗传分化的基本过程。通过在四个纬度梯度的城市中测试假设，该项目将确定环境背景如何影响进化结果。这名研究员将研究城市热量如何影响蜂鸟复杂温度调节特性的进化和遗传分化，蜂鸟是一种用于检测种群水平对气候变化反应的模型分类群。蜂鸟在所有恒温动物中具有最高的质量特异性代谢，而且储存的脂肪很少，这使它们对温度变化特别敏感，是探测种群对气候变化的反应的工具。该研究员将测量成对的城市和非城市蜂鸟种群的形态、行为（冬眠使用）、热耐受性（使用呼吸测量法）和每日能量消耗（使用双标签水）。利用下一代测序技术，该研究员将进行全基因组关联研究，以确定可能受到城市热量选择的基因组区域。研究将在纬度梯度上的四个城市进行，以描述温度调节特征的灵活性和由此产生的进化潜力如何在纬度上变化。通过与当地社区的合作，这项研究的成果将有助于设计更绿色的城市，既促进生物多样性，又减少城市热量对服务不足的人类社区的负面影响。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。

This action funds an NSF Postdoctoral Research Fellowship in Biology for FY 2023, Integrative Research Investigating the Rules of Life Governing Interactions Between Genomes, Environment, and Phenotypes. The fellowship supports research and training of the fellow that will contribute to the area of Rules of Life in innovative ways. Species are facing rapid changes in ambient temperature due to changing climate. To survive, organisms will need to adjust their physiology through a combination of phenotypic change and genetic change. Whether the rate and magnitude of these responses can match changes across environments with varying temperatures will determine whether populations persist or go locally extinct. This fellowship uses cities to study evolutionary responses to changing ambient temperatures on contemporary timescales. Replacement of vegetation with paved surfaces creates an Urban Heat Island (UHI) effect where mean and extreme temperatures are higher compared to undisturbed surroundings. The UHI effect is a nearly universal characteristic of cities worldwide, resulting in well-distributed, globally-replicated thermal gradients. By linking environmental, phenotypic, and genetic variation, results will shed light on the fundamental processes underlying the persistence, evolutionary potential, and genetic divergence of endothermic species facing warmer climates. By testing hypotheses in four cities across a latitudinal gradient, this project will determine how environmental context will shape evolutionary outcomes. The fellow will investigate how urban heat is affecting the evolution of complex thermoregulatory traits and genetic divergence in hummingbirds, a model taxon for detecting population-level responses to changing climate. Hummingbirds have some of the highest mass-specific metabolisms of all endotherms and store very little fat, making them particularly sensitive to changes in temperature and instrumental for detecting population-level responses to changing climate. The fellow will measure morphology, behavior (torpor use), thermal tolerance (using respirometry), and daily energy expenditure (using doubly-labeled water) of paired urban and non-urban hummingbird populations. Using next-generation sequencing, the fellow will then conduct a genome-wide association study to identify regions of the genome that may be under selection by urban heat. Studies will be conducted in four cities across a latitudinal gradient to describe how the flexibility of thermoregulatory traits and resulting evolutionary potential may vary across latitudes. And by engaging with local communities, the outcomes of this research will contribute to designing greener cities that both promote biodiversity and reduce the negative impacts of urban heat on underserved human communities.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.