Energy management and life history evolution in variable environments

可变环境中的能量管理和生命史进化

• 批准号: RGPIN-2020-06781
• 负责人: Lane, Jeffrey
• 金额: $ 2.04万
• 依托单位: University of Saskatchewan
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=741428
• 关键词: Energy; management; life; history; evolution

The energetic status of an individual is hypothesized to be a core influence on its reproductive output, but energetic measurements are typically made in laboratories, far removed from their eco-evolutionary context. My long-term goal is therefore to understand how environmental variation influences the energetic statuses of, and shapes the reproductive allocation decisions made by, wild animals. I will meet three short-term objectives over this granting cycle: (1) Determine the environmental and intrinsic influences on variation in levels of energy acquisition and assimilation in preparation for reproduction; (2) Test two hypothesized energetic mechanisms put forward to explain reproductive constraints during a single breeding event; and (3) Uncover relationships between breeding events that explain optimal energy allocation decisions across the lifetime. I will use a state-of-the-art mobile laboratory to characterize the energetic statuses of individuals within two established wild mammal study systems (the Rocky Mountain Ground Squirrel (RMGSP) and Kluane Red Squirrel Projects (KRSP)) as well as a new field study on Arctic ground squirrels (Urocitellus paryii) and a captive study on lab mice (Mus musculus). Specifically, I will use a quantitative magnetic body composition analyzer to measure energy stores (fat and lean mass) and open flow respirometry to measure energy use (metabolic rate). In the field projects, we will collect complete life history data for all individuals in fully censused populations against a backdrop of quantifiable environmental variation. In RMGSP, we will study the influences of natural and manipulated variation in food resources and weather on hibernation profiles and reproductive allocations of Columbian ground squirrels (U. columbianus). We will also collect detailed energetic data during hibernation of individuals from two different elevations in a common, captive environment. I will evaluate the generality of these findings by conducting a parallel study on wild Arctic ground squirrels. In KRSP, we will assess the determinants of variation in cached and on-body resources, and how this variation influences reproductive allocations made within and across breeding events in red squirrels (Tamiasciurus hudsonicus). We will also use a fur reduction experiment to test the hypothesis that limits on dissipating extra metabolically generated heat during reproduction can constrain output. In lab mice, I will study the interactive effects of fur reduction and calorie restriction on longevity and reproductive output. Variation in reproductive output is a central component in both population and microevolutionary dynamics, but a main contributor to this variation (energetic status) is typically treated as a `black-box'. By opening this black box, this research should produce results of both important fundamental and applied relevance.

一个个体的能量状态被假设为对其生殖产出的核心影响，但能量测量通常是在实验室进行的，远离它们的生态进化背景。因此，我的长期目标是了解环境变化如何影响野生动物的精力状态，并塑造野生动物做出的生殖分配决定。在这个授予周期中，我将实现三个短期目标：(1)确定环境和内在影响对繁殖准备过程中能量获取和同化水平的变化；(2)测试提出的两种假想的能量机制，以解释在单个繁殖事件期间的生殖限制；以及(3)揭示繁殖事件之间的关系，以解释整个生命周期的最佳能量分配决定。我将使用最先进的移动实验室来表征两个成熟的野生哺乳动物研究系统(落基山地松鼠(RMGSP)和克鲁恩红松鼠项目(KRSP))以及一项新的北极地松鼠(Urocitellus Paryii)野外研究和一项圈养小鼠(Mus Musculus)研究中个体的能量状态。具体地说，我将使用定量磁性身体成分分析仪来测量能量储存(脂肪和瘦肉质量)，并使用开放式呼吸测量仪来测量能量使用(代谢率)。在实地项目中，我们将在可量化的环境变化的背景下，收集完全普查人口中所有个人的完整生活史数据。在RMGSP中，我们将研究食物资源和天气的自然和人为变化对哥伦比亚黑松鼠冬眠特征和生殖分配的影响。我们还将收集来自两个不同海拔的个体在共同的圈养环境中冬眠期间的详细能量数据。我将通过对野生北极地松鼠进行一项平行研究来评估这些发现的普遍性。在KRSP中，我们将评估缓存资源和体内资源变异的决定因素，以及这种变异如何影响红松鼠(Tamiasciurus Hudsonicus)在繁殖事件中和跨繁殖事件中的生殖分配。我们还将使用毛皮减少实验来测试这样一个假设，即在繁殖过程中限制消耗额外的代谢产生的热量会限制输出。在实验室小鼠身上，我将研究皮毛减少和卡路里限制对寿命和生殖输出的交互影响。生殖产出的变异是种群和微进化动态的中心组成部分，但这种变异的一个主要因素(能量状态)通常被视为“黑箱”。通过打开这个黑匣子，这项研究应该会产生具有重要基础和应用相关性的结果。