It Costs to Be Clean and Fit: Energetics of Comfort Behavior in Breeding-Fasting Penguins
It Costs to Be Clean and Fit: Energetics of Comfort Behavior in Breeding-Fasting Penguins
复制标题
保持清洁和健康需要付出代价：禁食繁殖企鹅舒适行为的能量
作者：
Vincent A. Viblanc;Adeline Mathien;C. Saraux;Vanessa M. Viera;R. Groscolas
背景鸟类可能会将很大一部分时间分配给舒适的行为(例如，梳毛、伸展、抖动等)。以消除寄生虫，保持羽毛的完整性，并可能减少肌肉僵硬。了解舒适行为的适应价值将受益于动物愿意为维持舒适行为而支付的能源成本的知识，特别是在能量有限的情况下，例如在禁食期间。我们确定了在自由繁殖的王企鹅(Aptenodytes Patternicus)身上用于舒适活动的时间和精力，这种海鸟在孵化转移到岸边期间可以禁食长达一个月。方法/主要发现根据焦点和扫描采样现场观察估计时间预算，并使用先前确定的心率与能量消耗之间的关系式，根据舒适期间心率(HR)的相关增加来计算舒适活动的能量成本。我们发现，孵化中的雏鸟每天22%的时间用于舒适行为(昼夜没有差异)，主要用于打扮(73%)和摇头/身体(16%)。在舒适行为中，能量消耗是静息代谢率(RMR)的1.24倍，相应的能量成本(即超过RMR的能量消耗)为58kJ/小时。不同舒适度行为的能量消耗差异很大，从1.03倍(打哈欠)到1.78倍(伸展)。舒适行为对总能量消耗的贡献率为8.8%~9.3%，对日常活动能量消耗的贡献率为69.4%~73.5%。大约一半的精力都花在了照料羽毛上。结论/意义本研究首次估计了舒适行为对自由生活动物总能量收支的贡献。研究表明，尽管王企鹅繁殖的能量预算很紧张，但它们在舒适的行为上投入了大量的时间和精力。这些发现突显了舒适行为对殖民地海鸟健康的重要性。
Background Birds may allocate a significant part of time to comfort behavior (e.g., preening, stretching, shaking, etc.) in order to eliminate parasites, maintain plumage integrity, and possibly reduce muscular ankylosis. Understanding the adaptive value of comfort behavior would benefit from knowledge on the energy costs animals are willing to pay to maintain it, particularly under situations of energy constraints, e.g., during fasting. We determined time and energy devoted to comfort activities in freely breeding king penguins (Aptenodytes patagonicus), seabirds known to fast for up to one month during incubation shifts ashore. Methodology/Principal Findings A time budget was estimated from focal and scan sampling field observations and the energy cost of comfort activities was calculated from the associated increase in heart rate (HR) during comfort episodes, using previously determined equations relating HR to energy expenditure. We show that incubating birds spent 22% of their daily time budget in comfort behavior (with no differences between day and night) mainly devoted to preening (73%) and head/body shaking (16%). During comfort behavior, energy expenditure averaged 1.24 times resting metabolic rate (RMR) and the corresponding energy cost (i.e., energy expended in excess to RMR) was 58 kJ/hr. Energy expenditure varied greatly among various types of comfort behavior, ranging from 1.03 (yawning) to 1.78 (stretching) times RMR. Comfort behavior contributed 8.8–9.3% to total daily energy expenditure and 69.4–73.5% to energy expended daily for activity. About half of this energy was expended caring for plumage. Conclusion/Significance This study is the first to estimate the contribution of comfort behavior to overall energy budget in a free-living animal. It shows that although breeding on a tight energy budget, king penguins devote a substantial amount of time and energy to comfort behavior. Such findings underline the importance of comfort behavior for the fitness of colonial seabirds.