Common mechanics of mode switching in locomotion of limbless and legged animals
Common mechanics of mode switching in locomotion of limbless and legged animals
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DOI：
10.1098/rsif.2014.0205
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发表时间：
2014-06
影响因子：
3.9
通讯作者：
S. Kuroda;Itsuki Kunita;Yoshimi Tanaka;A. Ishiguro;R. Kobayashi;T. Nakagaki
中科院分区：
文献类型：
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作者：
S. Kuroda;Itsuki Kunita;Yoshimi Tanaka;A. Ishiguro;R. Kobayashi;T. Nakagaki
在许多物种中都观察到使用肌波爬行，包括涡虫、水蛭、纽虫、海兔、蜗牛、石鳖、蚯蚓和蛆。当履带体向后推动地面时，收缩波或伸展波沿着身体的前后轴传播。然而，在过去的一百年里，运动波可以向前或向后引导的观察引起了广泛的关注。蜈蚣和千足虫等有足生物表现出类似的现象；腿尖形成向后或向前传播的密度波。机械方面的考虑表明，腿密度波与无肢物种中的运动波发挥着相似的作用，并且运动波被有腿和无肢物种共有的机制用来实现爬行。在这里，我们报告在实验室中诱导向后运动时实现了波方向的模式切换和摩擦控制。我们表明，根据机械方面的考虑，不同动物的转换的许多变化基本上可以分为两种类型。我们认为，在进化过程中，无肢爬行者在获得腿之前首先以类似于行走的方式移动。因此，有腿的爬行者可能早在获得腿之前就已经学会了行走所涉及的机械运动模式。
Crawling using muscular waves is observed in many species, including planaria, leeches, nemertea, aplysia, snails, chitons, earthworms and maggots. Contraction or extension waves propagate along the antero-posterior axis of the body as the crawler pushes the ground substratum backward. However, the observation that locomotory waves can be directed forward or backward has attracted much attention over the past hundred years. Legged organisms such as centipedes and millipedes exhibit parallel phenomena; leg tips form density waves that propagate backward or forward. Mechanical considerations reveal that leg-density waves play a similar role to locomotory waves in limbless species, and that locomotory waves are used by a mechanism common to both legged and limbless species to achieve crawling. Here, we report that both mode switching of the wave direction and friction control were achieved when backward motion was induced in the laboratory. We show that the many variations of switching in different animals can essentially be classified in two types according to mechanical considerations. We propose that during their evolution, limbless crawlers first moved in a manner similar to walking before legs were obtained. Therefore, legged crawlers might have learned the mechanical mode of movement involved in walking long before obtaining legs.