Avian phenotypic transitions; acting constraints, mechanisms and consequences

该项目的长期目标是破译在面临高能量需求的鸟类中限制表型灵活性的机制，并确定这些限制对健康的影响。在接下来的五年里，我们将重点关注与寒冷气候下越冬、迁徙和繁殖相关的表型转变。在已知的脊椎动物和鸟类中，这些生活史阶段涉及最高的能量需求，被认为是影响身体组成和生理状况的能量瓶颈。更准确地说，我们将(1)确定代谢灵活性响应环境温度快速变化的速率和幅度，并测量表型与温度变化不匹配的生理后果。第一个项目将在UQAR鸟类设施进行，暴露三种模式物种（黑顶山雀，Poecile atricapillus，雪猎鸟，Plectrophenax nivalis，白喉麻雀，白喉麻雀和白喉麻雀）。随着时间的推移，通过跟踪个体代谢性能和生理状况的变化，白毛癣菌（Zonotrichia albicollis）的两个热梯度。我们还将(2)研究代谢表现如何影响个体适应度。这将在macp<e:1>研究森林进行，我们从2009年开始在那里与自由生活的山雀一起工作。冬季代谢性能、个体柔韧性、生理状况和衰老率都与生存和繁殖成功有关。使用雪猎作为我们的模型，我们还将(3)确定表型转变对这些北极迁徙者代谢表现的影响，并研究高北极地区（Alert, Nunavut）繁殖和体温调节的冲突需求如何在从迁徙到繁殖过渡期间塑造表型。这将包括整个冬季对室外圈养鸟类的重复测量，以及在迁徙前育肥期间和从它们到达繁殖地到繁殖结束期间对自由生活鸟类的测量。这个程序提供了形成适应性表型灵活性的生态和生理约束之间相互作用的综合理解。从长远来看，我们的研究将揭示鸟类表型灵活性在不同条件下的极限，并将有助于确定可能达到这些极限的自然约束。

The long-term objectives of this program are to decipher the mechanisms that limit phenotypic flexibility in birds facing high energy demands and to determine the consequences of these limits on fitness. Over the next five years, we will focus on phenotypic transitions associated with wintering in cold climates, migration and reproduction. These life-history stages involve energy demands among the highest known in vertebrates and, in birds, are considered energy bottlenecks affecting body composition and physiological condition. More precisely, we will (1) determine the rate and amplitude of metabolic flexibility in response to rapid changes in ambient temperature and measure the physiological consequences of phenotypes mismatched to temperature variations This first project will be conducted at the UQAR avian facility by exposing three models species (black-capped chickadees, Poecile atricapillus, snow buntings, Plectrophenax nivalis, white throated sparrow, Zonotrichia albicollis) to two thermal gradients and by tracking individual changes in metabolic performance and physiological condition over time. We will also (2) examine how metabolic performance influences individual fitness. This will be done at the Macpès research forest where we work with free-living chickadees since 2009. Winter metabolic performance, individual flexibility, physiological condition and aging rate will be related to both survival and reproductive success. Using snow buntings as our model, we will also (3) determine the effects of phenotypic transitions on metabolic performance of these Arctic migrants and investigate how conflicting demands for breeding and thermoregulation in the High-Arctic (Alert, Nunavut) shape phenotypes during the transition from migration to breeding. This will involve repeated measurements in outdoor captive birds throughout winter as well as measures on free-living birds during premigratory fattening and during the period from their arrival on the breeding ground to the end of breeding. This program provides an integrated comprehension of the interplay between ecological and physiological constraints that shape adaptive phenotypic flexibility. On the long term, our research will shed light on the limits of avian phenotypic flexibility in contrasting conditions and will help identify natural constraints in which these limits may be reached.