Witter M S, Cuthill I C
Department of Zoology, University of Bristol, U.K.
Philos Trans R Soc Lond B Biol Sci. 1993 Apr 29;340(1291):73-92. doi: 10.1098/rstb.1993.0050.
Avian fat storage is associated with both benefits and costs. Although the benefits of maintaining higher energetic reserves have long been considered, the associated costs have received far less attention. Spatial and temporal patterns of fat storage, together with experimental data, indicate that birds are capable of actively regulating their energetic reserves at levels below physiological or environmental maxima. This regulation implies that fat storage entails a cost. Evidence of potential costs are reviewed and discussed under the following headings: mass-dependent metabolism, mass-dependent predation risk, mass-dependent risk of injury, mass-dependent foraging, pathological costs and reproductive costs. Although the evidence that fat storage is costly is convincing, key empirical data are lacking. We indicate the sorts of data which need to be gathered and suggest ways in which this might be done. We go on to discuss the interaction of these costs and their relevance to between-individual patterns of fat storage and the interpretation of 'condition indices'. Because many of the purported costs of fat storage are dependent upon changes in body mass, or wing loading, our review is also relevant to other phenomena which may involve mass-dependent costs, such as gonadal hypertrophy, transport of food items and primary moult.
鸟类脂肪储存既有益处也有代价。尽管长期以来人们一直认为维持较高能量储备有诸多益处，但与之相关的代价却很少受到关注。脂肪储存的时空模式以及实验数据表明，鸟类能够将其能量储备主动调节至低于生理或环境最大值的水平。这种调节意味着脂肪储存是有代价的。本文将在以下标题下对潜在代价的证据进行综述和讨论：体重依赖性代谢、体重依赖性捕食风险、体重依赖性受伤风险、体重依赖性觅食、病理代价和繁殖代价。尽管脂肪储存存在代价这一证据很有说服力，但关键的实证数据仍很缺乏。我们指出了需要收集的数据类型，并提出了收集这些数据的方法。我们接着讨论这些代价之间的相互作用，以及它们与个体间脂肪储存模式和“身体状况指数”解读的相关性。由于许多所谓的脂肪储存代价取决于体重或翼载荷的变化，我们的综述也适用于其他可能涉及体重依赖性代价的现象，如性腺肥大、食物运输和初级换羽。
