Understanding growth and development over ontogeny, and the effects of stressors on life history, requires bioenergetic analysis, for example using models based on dynamic energy budget theory. Such analyses require precise and accurate determination of the animal's biomass or biovolume over time. Automated imaging offers great advantages by allowing size measurements at a high temporal resolution and the possibility to follow individual animals, thus providing detailed growth trajectories as well as handles on inter-individual variation in growth. Here we report on a re-analysis of images from a life-cycle experiment with the coastal harpacticoid copepod Tigriopus brevicornis. Biovolume was estimated by approximating the organism's shape by a generalised ellipsoid. This analysis confirmed, rather unsurprisingly, that the moult from the last naupliar to the first copepodite stage is accompanied by a major change in shape. However, within the naupliar and copepodite stages, more gradual elongation was observed. These changes in shape imply that total body length is a poor proxy for body size throughout the developmental stages, and is therefore not suitable for bioenergetic analysis. Volumetric length (cubic root of estimated body volume) is far more appropriate. Interestingly, growth ceases for some 1.5 days around the moult to the first copepodite stage. Such a growth stop was not observed in earlier studies of several other copepod species. Furthermore, the growth rate of the copepodites exceeded that of the nauplii. These complexities in the life history of T. brevicornis pose challenges for bioenergetic analysis that will require determination of additional traits (e.g., feeding and respiration rates) to unravel.

了解个体发育的生长和发育，以及压力源对生活史的影响，需要生物能量分析，例如使用基于动态能量预算理论的模型。此类分析需要随着时间的推移精确确定动物的生物量或生物量。自动成像提供了巨大的优势，允许以高时间分辨率进行尺寸测量，并且可以跟踪单个动物，从而提供详细的生长轨迹以及处理个体间生长变化的方法。在这里，我们报告了对沿海 harpacticoid 桡足类Tigriopus brevicornis生命周期实验图像的重新分析. 生物体积是通过用广义椭圆体近似生物体的形状来估计的。毫不奇怪，这一分析证实，从最后一个无节幼体到第一个桡足类阶段的蜕皮伴随着形状的重大变化。然而，在无节幼体和桡足体阶段，观察到更逐渐的伸长。这些形状的变化意味着整个身体长度在整个发育阶段不能很好地代表身体大小，因此不适合生物能量分析。体积长度（估计体积的立方根）更合适。有趣的是，从蜕皮到第一桡足类阶段，生长停止了大约 1.5 天。在早期对其他几种桡足类物种的研究中没有观察到这种生长停止。此外，桡足类的生长速度超过了无节幼体。生活史中的这些复杂性T. brevicornis对生物能量分析提出了挑战，需要确定其他特征（例如，进食和呼吸速率）才能解开。