Metcalfe N B, Van Leeuwen T E, Killen S S
Institute of Biodiversity, Animal Health & Comparative Medicine, Graham Kerr Building, University of Glasgow, Glasgow G12 8QQ, U.K.
Scottish Centre for Ecology and the Natural Environment (SCENE), University of Glasgow, Rowardennan, Loch Lomond, Glasgow G63 0AW, U.K.
J Fish Biol. 2016 Jan;88(1):298-321. doi: 10.1111/jfb.12699. Epub 2015 Nov 17.
There is increasing interest in documenting and explaining the existence of marked intraspecific variation in metabolic rate in animals, with fishes providing some of the best-studied examples. After accounting for variation due to other factors, there can typically be a two to three-fold variation among individual fishes for both standard and maximum metabolic rate (SMR and MMR). This variation is reasonably consistent over time (provided that conditions remain stable), and its underlying causes may be influenced by both genes and developmental conditions. In this paper, current knowledge of the extent and causes of individual variation in SMR, MMR and aerobic scope (AS), collectively its metabolic phenotype, is reviewed and potential links among metabolism, behaviour and performance are described. Intraspecific variation in metabolism has been found to be related to other traits: fishes with a relatively high SMR tend to be more dominant and grow faster in high food environments, but may lose their advantage and are more prone to risk-taking when conditions deteriorate. In contrast to the wide body of research examining links between SMR and behavioural traits, very little work has been directed towards understanding the ecological consequences of individual variation in MMR and AS. Although AS can differ among populations of the same species in response to performance demands, virtually nothing is known about the effects of AS on individual behaviours such as those associated with foraging or predator avoidance. Further, while factors such as food availability, temperature, hypoxia and the fish's social environment are known to alter resting and MMRs in fishes, there is a paucity of studies examining how these effects vary among individuals, and how this variation relates to behaviour. Given the observed links between metabolism and measures of performance, understanding the metabolic responses of individuals to changing environments will be a key area for future research because the environment will have a strong influence on which animals survive predation, become dominant and ultimately have the highest reproductive success. Although current evidence suggests that variation in SMR may be maintained within populations via context-dependent fitness benefits, it is suggested that a more integrative approach is now required to fully understand how the environment can modulate individual performance via effects on metabolic phenotypes encompassing SMR, MMR and AS.
记录和解释动物代谢率存在显著种内变异的现象并对其加以阐释，这一兴趣日益浓厚，鱼类提供了一些研究最为深入的实例。在排除其他因素导致的变异后，个体鱼类的标准代谢率和最大代谢率（SMR和MMR）通常会有两到三倍的差异。这种变异在一段时间内相当稳定（前提是条件保持稳定），其潜在原因可能受到基因和发育条件的影响。本文综述了关于SMR、MMR和有氧代谢范围（AS）个体变异的程度和原因的现有知识，这些统称为代谢表型，并描述了代谢、行为和性能之间的潜在联系。已发现代谢的种内变异与其他性状有关：SMR相对较高的鱼类往往更具优势，在食物丰富的环境中生长更快，但当条件恶化时可能会失去优势，并且更容易冒险。与大量研究SMR与行为性状之间联系的工作形成对比的是，针对理解MMR和AS个体变异的生态后果的研究极少。尽管AS可能因同一物种的不同种群对性能需求的反应而有所不同，但对于AS对个体行为（如与觅食或躲避捕食者相关的行为）的影响几乎一无所知。此外，虽然已知食物供应、温度、缺氧和鱼类的社会环境等因素会改变鱼类的静息代谢率和MMR，但很少有研究探讨这些影响在个体间如何变化，以及这种变异与行为有何关系。鉴于已观察到代谢与性能指标之间的联系，了解个体对不断变化的环境的代谢反应将是未来研究的一个关键领域，因为环境将对哪些动物能够在捕食中存活、占据优势并最终获得最高繁殖成功率产生重大影响。尽管目前的证据表明，SMR的变异可能通过依赖于环境的适应性益处而在种群中得以维持，但有人建议现在需要一种更综合的方法来全面理解环境如何通过对包括SMR、MMR和AS的代谢表型的影响来调节个体性能。
