Metabolic activation can have a profound impact, for instance, by more than compensating for the lower resting metabolic rates of large organisms compared to smaller ones. In some animals, activity can easily be judged by the rate of muscle-driven movement. In sessile organisms, however, judging activity is less straightforward, although feeding often results in metabolic activation. Two colonial cnidarians were examined in this context, using entirely lab-grown material to remove any artifactual effects of experimental manipulations. Hydractinia symbiolongicarpus is a carnivorous hydroid that uses active muscular contractions to drive its gastrovascular fluid. Sympodium sp., on the other hand, is an octocoral that hosts photosynthetic Symbiodinium and uses cilia to propel its gastrovascular fluid. Measures of oxygen uptake indicated that feeding activated metabolism in H. symbiolongicarpus. While light treatment had no effect on subsequent dark metabolism in Sympodium sp., stress activated metabolism to an extent comparable to H. symbiolongicarpus. In both taxa, different individual size measures or synthetic size measures derived from principal component analysis produced different scaling relationships between metabolism and size. On balance, the data suggest that scaling was negatively allometric in Sympodium sp. and nearly isometric in H. symbiolongicarpus; yet metabolic activation was comparable in the two species. Regardless of the size measure used, active and resting colonies of H. symbiolongicarpus exhibited similar scaling relationships. Colonial animals may lack the large difference between resting and active metabolic rates found in highly active animals, and this may be related to how their metabolism scales with size.

中文翻译：

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两种殖民地刺胞动物的代谢激活和缩放

代谢激活可以产生深远的影响，例如，与较小的生物相比，它不仅可以补偿大型生物体的较低静息代谢率。在一些动物中，活动可以很容易地通过肌肉驱动的运动速度来判断。然而，在固着生物中，判断活动不那么直接，尽管进食通常会导致代谢激活。在这种情况下检查了两个殖民地刺胞动物，使用完全实验室生长的材料来消除实验操作的任何人为影响。Hydractinia symbiolongicarpus 是一种肉食性水螅，它使用主动的肌肉收缩来驱动其胃肠液。另一方面，Sympodium sp. 是一种八珊瑚，其宿主光合作用 Symbiodinium 并使用纤毛推动其胃肠液。摄氧量的测量表明喂食激活了共生龙舌兰的新陈代谢。虽然光处理对 Sympodium sp. 中随后的暗代谢没有影响，但应激激活代谢的程度与 H. symbiolongicarpus 相当。在这两个分类群中，不同的个体大小测量或从主成分分析得出的合成大小测量在代谢和大小之间产生不同的比例关系。总的来说，数据表明在 Sympodium sp. 中缩放是负异速生长的。在 H. symbiolongicarpus 中几乎等距；然而代谢活化在这两个物种中是可比的。无论使用何种大小测量，H. symbiolongicarpus 的活跃和静止集落都表现出类似的缩放关系。