Costs of Incubation: Linking Incubation-Induced Alterations in Phenotype to Changes in Fitness

蛋的孵化是鸟类繁殖的关键部分。胚胎的最佳生长和发育发生在狭窄的孵化温度范围内，父母必须平衡保持良好的身体状况和照顾发育中的卵子的竞争需求。在鸟类繁殖成本的研究中，孵化的重要性往往被忽视，但孵化成本可能限制当前和未来的繁殖成功。在只有一种性别的物种中，时间和能量的需求尤为重要。孵蛋的父母出勤的减少更有可能使蛋的温度偏离最佳发育所需的温度。卵温过低会减缓发育，导致孵化期延长，从而导致更大的捕食风险，并可能影响胚胎发育和最终新生儿表型所消耗的能量。对木鸭的研究将有三个主要组成部分。首先，以往的实验工作表明，孵育温度对木鸭的孵育期和雏鸭表型都有影响。该项目将利用孵化温度来控制雏鸭的表型，然后将一天大的雏鸭送回养母饲养。这些温度引起的雏鸭表型变化对雏鸭生长发育、存活、繁殖群体招募和随后的繁殖成功的影响将被研究。其次，评估孵化温度对木鸭胚胎代谢率和总能量消耗的影响。随后，我们将对不同温度下孵化的雏鸭的体温调节能力和体温调节的能量消耗进行研究。第三，将对成虫的孵化成本进行操纵，并研究这些操纵成本对体重动力学、孵化行为、季节内和季节间繁殖性能以及雌性存活率的影响。该项目将使用生活史框架来检查产妇生育决定对健康的影响。研究结果将重新激发鸟类孵化模式及其功能影响的研究，并为我们理解脊椎动物生活史策略的进化做出新的贡献。研究与教育的整合将是该项目的一个重要目标。这将通过(1)将新的研究成果纳入本科和研究生课程，(2)招募本科生和研究生参与该项目，(3)在萨凡纳河生态实验室为nsf资助的本科生举办研讨会，展示实地研究和数据管理方法，以及(4)整合K-12的水禽繁殖活动。弗吉尼亚理工大学的科学推广计划（SOuP）将科学研究带给更广泛的受众，特别是K-12的教师和学生。

Incubation of eggs is a critical part of reproduction in birds. Optimal growth and development of embryos takes place within a narrow range of incubation temperatures, and parents must balance the competing demands of maintaining good body condition while caring for developing eggs. The importance of incubation has often been overlooked in studies of avian reproductive costs, but incubation costs can limit both current and future reproductive success. Time and energy demands can be especially important in species where only one sex incubates. Reduced attendance by incubating parents makes it more likely that egg temperatures will deviate from that needed for optimal development. Low egg temperatures can slow development and lead to longer incubation periods, which results in greater predation risk and potentially influences the amount of energy used by developing embryos and ultimately neonate phenotype. This research with wood ducks will have 3 main components. First, previous experimental work has shown that incubation temperature influenced both incubation period and neonate phenotype of wood ducks. This project will use incubation temperature to manipulate phenotypes of neonates and then return day-old ducklings to foster mothers to raise. Effects of these temperature-induced changes to duckling phenotype on growth and development, survival, recruitment to the breeding population, and subsequent reproductive success will be examined. Second, effects of incubation temperature on metabolic rates and total energy expended by wood duck embryos will be estimated. Later, ability of ducklings incubated at different temperatures to thermoregulate and the energetic costs of thermoregulation also will be examined. Third, incubation costs of adults will be manipulated and effects of these manipulated costs on body mass dynamics, incubation behavior, within- and between-season reproductive performance, and survival of females will be examined. The project will use a life history framework to examine fitness consequences of maternal reproductive decisions. Results should re-invigorate studies of incubation patterns and their functional consequences in birds, and make new contributions to our understanding of the evolution of vertebrate life history strategies. Integration of research and education will be an important goal of the project. This will be accomplished by (1) incorporating new research findings in undergraduate and graduate courses, (2) recruiting undergraduate and graduate students to work on the project, (3) hosting a workshop for NSF-sponsored undergraduates at the Savannah River Ecology Laboratory to demonstrate field research and data management methods, and (4) integrating a K-12 activity on waterfowl reproduction, conservation and education with the Virginia Tech's Science Outreach Program (SOuP) which brings science research to broader audiences, especially K-12 teachers and students.