Santer Roger D, Yamawaki Yoshifumi, Rind F Claire, Simmons Peter J
School of Biology, Ridley Building, University of Newcastle upon Tyne, UK.
J Comp Physiol A Neuroethol Sens Neural Behav Physiol. 2005 Oct;191(10):965-75. doi: 10.1007/s00359-005-0023-3. Epub 2005 Sep 29.
We investigated the escape jumps that locusts produce in response to approaching objects. Hindleg muscular activity during an escape jump is similar to that during a defensive kick. Locusts can direct their escape jumps up to 50 degrees either side of the direction of their long axis at the time of hindleg flexion, allowing them to consistently jump away from the side towards which an object is approaching. Variation in jump trajectory is achieved by rolling and yawing movements of the body that are controlled by the fore- and mesothoracic legs. During hindleg flexion, a locust flexes the foreleg ipsilateral to its eventual jump trajectory and then extends the contralateral foreleg. These foreleg movements continue throughout co-contraction of the hindleg tibial muscles, pivoting the locust's long axis towards its eventual jump trajectory. However, there are no bilateral differences in the motor programs of the left and right hindlegs that correlate with jump trajectory. Foreleg movements enable a locust to control its jump trajectory independent of the hindleg motor program, allowing a decision on jump trajectory to be made after the hindlegs have been cocked in preparation for a jump.
我们研究了蝗虫对接近物体所做出的逃避性跳跃。逃避性跳跃过程中后肢的肌肉活动与防御性踢腿时相似。在准备后肢弯曲时，蝗虫能够将其逃避性跳跃的方向指向其身体长轴方向两侧达50度，从而使其能够持续地从物体接近的一侧跳开。跳跃轨迹的变化是通过由前胸和中胸腿部控制的身体滚动和偏航运动来实现的。在后肢弯曲过程中，蝗虫会弯曲其最终跳跃轨迹同侧的前腿，然后伸展对侧的前腿。这些前腿运动在整个后肢胫部肌肉共同收缩期间持续进行，使蝗虫的身体长轴朝着其最终跳跃轨迹转动。然而，左右后肢的运动程序中不存在与跳跃轨迹相关的双侧差异。前腿运动使蝗虫能够独立于后肢运动程序来控制其跳跃轨迹，从而使得在为跳跃而准备将后肢弯曲之后再做出关于跳跃轨迹的决定成为可能。
