Slingshot spiders build tensed, underdamped webs for ultrafast launches and speedy halts
Slingshot spiders build tensed, underdamped webs for ultrafast launches and speedy halts
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DOI：
10.1007/s00359-021-01475-5
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发表时间：
2021-03-15
影响因子：
2.1
通讯作者：
Bhamla, M. Saad
中科院分区：
文献类型：
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作者：
Challita, Elio J.;Alexander, Symone L. M.;Bhamla, M. Saad
我们开发了一个数学模型来捕捉弹弓蜘蛛（蜘蛛目：球蛛科），利用张力线变形成圆锥形弹簧的球网捕食飞行昆虫的网络动力学。弹弓蜘蛛的特点是其超快的发射速度和加速度（超过1300米/秒（2）），然而，一个理论的方法来表征潜在的时空网络动力学仍然缺失。为了解决这个知识缺口，我们开发了一个二维耦合阻尼振荡器模型的网络。我们的模型揭示了弹弓运动动力学的三个关键见解。首先，张力线发挥着双重作用：使蜘蛛能够将弹性能量加载到网中，以便快速启动（以毫秒为单位）至10-15个体长的位移，而且还使蜘蛛能够快速停止，衰减惯性振荡。第二，主要的能量耗散机制是丝线的粘性阻力-充当低雷诺数降落伞。第三，通过径向线力、张力线力和粘性阻力耗散之间的微调平衡，腹板表现出欠阻尼振荡动力学。总之，我们的工作表明，圆锥形的几何形状和张力线，使弹弓网作为一个弹性弹簧和减震器，多功能的角色，冒险捕食和自我保护。
We develop a mathematical model to capture the web dynamics of slingshot spiders (Araneae: Theridiosomatidae), which utilize a tension line to deform their orb webs into conical springs to hunt flying insects. Slingshot spiders are characterized by their ultrafast launch speeds and accelerations (exceeding 1300 m/s(2)), however a theoretical approach to characterize the underlying spatiotemporal web dynamics remains missing. To address this knowledge gap, we develop a 2D-coupled damped oscillator model of the web. Our model reveals three key insights into the dynamics of slingshot motion. First, the tension line plays a dual role: enabling the spider to load elastic energy into the web for a quick launch (in milliseconds) to displacements of 10-15 body lengths, but also enabling the spider to halt quickly, attenuating inertial oscillations. Second, the dominant energy dissipation mechanism is viscous drag by the silk lines - acting as a low Reynolds number parachute. Third, the web exhibits underdamped oscillatory dynamics through a finely-tuned balance between the radial line forces, the tension line force and viscous drag dissipation. Together, our work suggests that the conical geometry and tension-line enables the slingshot web to act as both an elastic spring and a shock absorber, for the multi-functional roles of risky predation and self-preservation.