School of Life Sciences, Joseph Banks Laboratories, University of Lincoln, Beevor Street, Lincoln, LN6 7DL, England, UK.
J Comp Physiol B. 2023 Mar;193(2):145-153. doi: 10.1007/s00360-022-01471-4. Epub 2023 Jan 30.
Locusts (Schistocerca gregaria) jump using a latch mediated spring actuated system in the femur-tibia joint of their metathoracic legs. These jumps are exceptionally fast and display angular rotation immediately after take-off. In this study, we focus on the angular velocity, at take-off, of locusts ranging between 0.049 and 1.50 g to determine if and how rotation-rate scales with size. From 263 jumps recorded from 44 individuals, we found that angular velocity scales with mass, consistent with a hypothesis of locusts having a constant rotational kinetic energy density. Within the data from each locust, angular velocity increased proportionally with linear velocity, suggesting the two cannot be independently controlled and thus a fixed energy budget is formed at take-off. On average, the energy budget of a jump is distributed 98.7% to translational kinetic energy and gravitational potential energy, and 1.3% to rotational kinetic energy. The percentage of energy devoted to rotation was constant across all sizes of locusts and represents a very small proportion of the energy budget. This analysis suggests that smaller locusts find it harder to jump without body rotation.
蝗虫（Schistocerca gregaria）通过其后胸腿的股骨-胫骨关节中的闩锁介导的弹簧致动系统进行跳跃。这些跳跃非常快，并在起飞后立即显示出角旋转。在这项研究中，我们专注于 0.049 到 1.50 g 之间的蝗虫在起飞时的角速度，以确定旋转速度是否以及如何与大小成比例。我们从 44 只个体中记录了 263 次跳跃，发现角速度与质量成比例，这与蝗虫具有恒定旋转动能密度的假设一致。在每只蝗虫的数据中，角速度与线性速度成比例增加，这表明两者不能独立控制，因此在起飞时形成了固定的能量预算。平均而言，跳跃的能量预算分布为 98.7%用于平移动能和重力势能，1.3%用于旋转动能。旋转所消耗的能量百分比在所有大小的蝗虫中都是恒定的，仅占能量预算的很小一部分。这项分析表明，较小的蝗虫在不进行身体旋转的情况下更难以跳跃。
