Data for: Pendulum-based measurements reveal impact dynamics at the scale of a trap-jaw ant

Small organisms can produce powerful, sub-millisecond impacts by moving tiny structures at high accelerations. We developed and validated a pendulum device to measure the impact energetics of microgram-sized trap-jaw ant mandibles accelerated against targets at 105 m s-2. Trap-jaw ants (Odontomachus brunneus; 19 individuals; 212 strikes) were suspended on one pendulum and struck swappable targets that were either attached to an opposing pendulum or fixed in place. Mean post-impact kinetic energy (energy from strike converted to pendulum motion) was higher with a stiff target (21.0-21.5 µJ) than a compliant target (6.4-6.5 µJ). Target mobility had relatively little influence. Mean contact duration of strikes against stiff targets was shorter (3.9-4.5 ms) than against compliant targets (6.2-7.9 ms). Shorter contact duration was correlated with higher post-impact kinetic energy. These findings contextualize and provide an energetic explanation for the diverse, natural uses of trap-jaw ant strikes such as impaling prey, launching away threats, and performing mandible-powered jumps. The strong effect of target material on energetic exchange suggests material interactions as an avenue for tuning performance of small, high acceleration impacts. Our device offers a foundation for novel research into the ecomechanics and evolution of tiny biological impacts and their application in synthetic systems.

小型生物可通过以极高加速度驱动微小结构运动，产生威力强劲的亚毫秒级冲击。我们研发并验证了一套摆锤装置，用于测量颚部以105 m·s⁻²的加速度撞击靶标的微克级大齿猛蚁（trap-jaw ant）的冲击能量学特性。本次实验所用的大齿猛蚁（Odontomachus brunneus，共19只个体，累计212次攻击）被悬挂于一台摆锤之上，撞击可更换的靶标；这些靶标要么连接于对向摆锤，要么固定不动。撞击后平均动能（即由攻击转化为摆锤运动的能量）在刚性靶标条件下（21.0~21.5 微焦）高于柔性靶标条件下（6.4~6.5 微焦）。靶标的可动性对该能量的影响相对较小。相较于柔性靶标（6.2~7.9 毫秒），撞击刚性靶标的平均接触时长更短（3.9~4.5 毫秒）。接触时长越短，撞击后动能越高，二者呈相关关系。本研究结果为大齿猛蚁攻击行为的多样自然用途提供了场景化背景与能量学解释，这些用途包括刺穿猎物、驱离威胁以及依靠颚部完成跳跃。靶标材料对能量交换的显著影响表明，材料相互作用可作为调控小型高加速度冲击性能的途径。本装置为小型生物冲击的生态力学、演化机制及其在合成系统中的应用相关的创新研究奠定了基础。