Body size is central to ecology at levels ranging from organismal fecundity to the functioning of communities and ecosystems. Understanding temperature‐induced variations in body size is therefore of fundamental and applied interest, yet thermal responses of body size remain poorly understood. Temperature–size (T–S) responses tend to be negative (e.g. smaller body size at maturity when reared under warmer conditions), which has been termed the temperature–size rule (TSR). Explanations emphasize either physiological mechanisms (e.g. limitation of oxygen or other resources and temperature‐dependent resource allocation) or the adaptive value of either a large body size (e.g. to increase fecundity) or a short development time (e.g. in response to increased mortality in warm conditions). Oxygen limitation could act as a proximate factor, but we suggest it more likely constitutes a selective pressure to reduce body size in the warm: risks of oxygen limitation will be reduced as a consequence of evolution eliminating genotypes more prone to oxygen limitation. Thus, T–S responses can be explained by the ‘Ghost of Oxygen‐limitation Past’, whereby the resulting (evolved) T–S responses safeguard sufficient oxygen provisioning under warmer conditions, reflecting the balance between oxygen supply and demands experienced by ancestors. T–S responses vary considerably across species, but some of this variation is predictable. Body‐size reductions with warming are stronger in aquatic taxa than in terrestrial taxa. We discuss whether larger aquatic taxa may especially face greater risks of oxygen limitation as they grow, which may be manifested at the cellular level, the level of the gills and the whole‐organism level. In contrast to aquatic species, terrestrial ectotherms may be less prone to oxygen limitation and prioritize early maturity over large size, likely because overwintering is more challenging, with concomitant stronger end‐of season time constraints. Mechanisms related to time constraints and oxygen limitation are not mutually exclusive explanations for the TSR. Rather, these and other mechanisms may operate in tandem. But their relative importance may vary depending on the ecology and physiology of the species in question, explaining not only the general tendency of negative T–S responses but also variation in T–S responses among animals differing in mode of respiration (e.g. water breathers versus air breathers), genome size, voltinism and thermally associated behaviour (e.g. heliotherms).

中文翻译：

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因变暖而缩小的身体尺寸：对温度-尺寸规则的解释，特别强调氧气的作用

从生物体的繁殖力到群落和生态系统的功能，体型对于生态学来说至关重要。因此，了解温度引起的身体尺寸变化具有基础和应用意义，但对身体尺寸的热响应仍然知之甚少。温度-体型（T-S）反应往往是负的（例如，在较温暖的条件下饲养时，成熟时体型较小），这被称为温度-体型规则（TSR）。解释强调生理机制（例如氧气或其他资源的限制以及温度依赖性资源分配）或大体型（例如增加繁殖力）或短发育时间（例如应对温暖环境中死亡率增加）的适应性价值。状况）。缺氧可能是一个直接因素，但我们认为它更有可能构成一种选择压力，以减少温暖中的体型：由于进化消除了更容易缺氧的基因型，缺氧的风险将会降低。因此，T-S 反应可以用“过去的氧气限制幽灵”来解释，由此产生的（进化的）T-S 反应可以在温暖的条件下保证足够的氧气供应，反映了祖先经历的氧气供应和需求之间的平衡。不同物种的 T-S 反应差异很大，但其中一些差异是可以预测的。随着气候变暖，水生类群的体型减小程度比陆地类群更强。我们讨论较大的水生类群在生长过程中是否可能面临更大的缺氧风险，这可能表现在细胞水平、鳃水平和整个生物体水平上。与水生物种相比，陆地变温动物可能不太容易受到氧气限制，并且优先考虑早熟而不是大尺寸，这可能是因为越冬更具挑战性，同时伴随着更强的季节结束时间限制。与时间限制和氧气限制相关的机制并不是对 TSR 相互排斥的解释。相反，这些机制和其他机制可以协同运作。但它们的相对重要性可能会根据所讨论物种的生态学和生理学而有所不同，这不仅解释了负 T-S 反应的一般趋势，而且还解释了不同呼吸模式的动物之间 T-S 反应的变化（例如，水呼吸动物与水呼吸动物）空气呼吸器）、基因组大小、voltinism 和热相关行为（例如日温热动物）。