What is the functional effect of prolonged development? By controlling for size, we quantify first‐feeding performance and hydrodynamics of zebrafish and guppy offspring (5 ± 0.5 mm in length), which differ fivefold in developmental time and twofold in ontogenetic state. By manipulating water viscosity, we control the hydrodynamic regime, measured as Reynolds number. We predicted that if feeding performance were strictly the result of hydrodynamics, and not development, feeding performance would scale with Reynolds number. We find that guppy offspring successfully feed at much greater distances to prey (1.0 vs. 0.2 mm) and with higher capture success (90 vs. 20%) compared with zebrafish larvae, and that feeding performance was not a result of Reynolds number alone. Flow visualization shows that zebrafish larvae produce a bow wave ~0.2 mm in length, and that the flow field produced during suction does not extend beyond this bow wave. Due to well‐developed oral jaw protrusion, the similar‐sized suction field generated by guppy offspring extends beyond the horizon of their bow wave, leading to successful prey capture from greater distances. These findings suggest that prolonged development and increased ontogenetic state provides first‐feeding fish time to escape the pervasive hydrodynamic constraints (bow wave) of being small.

中文翻译：

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更长的开发时间为首次喂鱼提供了摆脱水动力限制的时间

长期发育的功能影响是什么？通过控制大小，我们量化了斑马鱼和孔雀鱼后代（长度为 5 ± 0.5 毫米）的首次进食性能和流体动力学，它们的发育时间差异为五倍，个体发育状态差异为两倍。通过操纵水的粘度，我们控制了以雷诺数测量的流体动力学状态。我们预测，如果饲养性能严格取决于流体动力学而不是发育，饲养性能将与雷诺数成比例。我们发现，与斑马鱼幼虫相比，孔雀鱼后代成功地以更远的距离捕食猎物（1.0 对 0.2 毫米）和更高的捕获成功率（90 对 20%），并且喂养性能并不仅仅取决于雷诺数。流动可视化显示斑马鱼幼虫产生约 0.2 毫米长的弓波，并且在吸入过程中产生的流场不会超出这个弓波。由于发育良好的口腔颌骨突出，孔雀鱼后代产生的类似大小的吸力场延伸到其弓波的地平线之外，从而成功地从更远的距离捕获猎物。这些发现表明，延长的发育和增加的个体发育状态为首次喂食的鱼提供了时间，以逃避普遍存在的水动力限制（弓浪）。