Department of Zoology, University of Cambridge, Cambridge, UK.
J Comp Physiol A Neuroethol Sens Neural Behav Physiol. 2021 Mar;207(2):165-177. doi: 10.1007/s00359-021-01466-6. Epub 2021 Mar 10.
Many spiders and insects can perform rapid jumps from smooth plant surfaces. Here, we investigate how jumping spiders (Pseudeuophrys lanigera and Sitticus pubescens) avoid slipping when accelerating. Both species differed in the relative contribution of leg pairs to the jump. P. lanigera accelerated mainly with their long third legs, whereas their short fourth legs detached earlier. In contrast, S. pubescens accelerated mainly with their long fourth legs, and their short third legs detached earlier. Because of the different orientation (fourth-leg tip pointing backward, third-leg tip pointing forward), the fourth-leg tarsus pushed, whereas the third-leg tarsus pulled. High-speed video recordings showed that pushing and pulling was achieved by different attachment structures. In P. lanigera, third-leg feet made surface contact with setae on their distal or lateral claw tuft, whereas fourth-leg feet engaged the proximal claw tuft, and the distal tuft was raised off the ground. S. pubescens showed the same division of labour between proximal and distal claw tuft for pushing and pulling, but the claw tuft contact lasted longer and was more visible in the fourth than in the third legs. Experimental ablation of claw tufts caused accelerating spiders to slip, confirming that adhesion is essential for jumps from smooth substrates.
许多蜘蛛和昆虫都可以从光滑的植物表面快速跳跃。在这里，我们研究了跳蛛（Pseudeuophrys lanigera 和 Sitticus pubescens）在加速时如何避免打滑。这两个物种的腿对跳跃的相对贡献不同。P. lanigera 主要用它们的长第三腿加速，而它们的短第四腿则更早脱离。相比之下，S. pubescens 主要用它们的长第四腿加速，而它们的短第三腿则更早脱离。由于第四腿的末端指向后方，第三腿的末端指向前方，所以第四腿的跗节推动，而第三腿的跗节拉动。高速视频记录显示，推动和拉动是通过不同的附着结构实现的。在 P. lanigera 中，第三腿的足部与远端或侧向爪簇上的刚毛接触，而第四腿的足部与近端爪簇接触，远端爪簇离开地面。S. pubescens 在推动和拉动时，近端和远端爪簇之间也有同样的分工，但第四腿的爪簇接触持续时间更长，而且比第三腿更明显。对爪簇的实验消融会导致加速的蜘蛛打滑，这证实了附着对于从光滑的基质上跳跃是必不可少的。
