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

这一行动为NSF 2023财年生物学博士后研究奖学金提供了资金，综合研究调查了支配基因组、环境和表型之间相互作用的生命规则。该奖学金支持研究员的研究和培训，这些研究员将以创新的方式为生活规则领域做出贡献。由于气候变化，物种面临着环境温度的快速变化。为了生存，生物体将需要通过表型变化和遗传变化相结合的方式来调整自己的生理。这些反应的速度和幅度能否在不同温度的环境中匹配变化，将决定种群是持续存在还是局部灭绝。该研究会使用城市来研究在当代时间尺度上对环境温度变化的进化反应。用铺好的地面替换植被会产生城市热岛(UHI)效应，与未受干扰的环境相比，这里的平均和极端温度更高。城市热岛效应几乎是世界各地城市的普遍特征，导致了均匀分布的、全球复制的温度梯度。通过将环境、表型和遗传变异联系起来，结果将阐明面临较暖气候的吸热物种的持久性、进化潜力和遗传差异背后的基本过程。通过对横跨纬度梯度的四个城市的假设进行测试，该项目将确定环境背景将如何影响进化结果。这位研究员将研究城市高温如何影响蜂鸟复杂的体温调节特征的进化和遗传分化，蜂鸟是一种探测种群水平对气候变化反应的模式分类群。蜂鸟在所有吸热动物中具有最高的质量比代谢，并且储存的脂肪非常少，这使得它们对温度变化特别敏感，并有助于检测种群水平对气候变化的反应。这位研究员将测量成对的城市和非城市蜂鸟种群的形态、行为(麻木使用)、耐热性(使用呼吸测量法)和每日能量消耗(使用双标记水)。利用下一代测序，这位研究员将进行全基因组关联研究，以确定可能受到城市炎热选择的基因组区域。研究将在横跨纬度梯度的四个城市进行，以描述体温调节特征的灵活性和由此产生的进化潜力如何在纬度之间变化。通过与当地社区的接触，这项研究的结果将有助于设计更绿色的城市，既促进生物多样性，又减少城市高温对服务不足的人类社区的负面影响。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。

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.