Jamming visual systems with stripes: the mesmerising hunting display of the broadclub cuttlefish

高对比度条纹通过改变对目标轨迹和速度的估计而在人类中产生运动错觉而闻名。条纹图案在自然界中也很普遍，从昆虫到哺乳动物。然而，关于动物是否以及如何进化出这种模式来扰乱、干扰或破坏目标视觉系统的实验证据仍然很少。该项目旨在通过调查高对比度条纹在真实的生物捕食者-猎物相互作用中的作用，收集第一个支持运动眩光在自然界中使用的明确证据，即阔俱乐部乌贼捕食螃蟹。这种墨鱼有一种独特的捕猎技巧。当接近猎物时，它会在头部和手臂上显示出高度对比鲜明的向下移动的条纹。我们的初步数据不仅表明，当一个接近的刺激物的特征是移动的条纹而不是静止的条纹时，螃蟹需要更大的对比度来引起逃跑反应，而且这种效果取决于条纹的速度。运动检测算法的实现进一步表明，螃蟹的反应可能会被一个覆盖的向下运动线索所改变，这与一个接近的捕食者所期望的非常不同，从而掩盖了迫在眉睫的墨鱼。利用捕食者模拟实验、跟踪程序和生物信息运动检测算法，本研究旨在：1)描述整个刺激空间中狩猎显示的影响，并测试墨鱼的自然狩猎行为是否被优化到干扰螃蟹的视觉；2)确定broadclub狩猎显示发生的精细尺度背景；3)从蟹的视觉角度重构了蟹的捕食序列，描述了蟹的条纹显示引起的光流模式。这项研究有可能在感官生物学领域产生强烈的影响，对机器视觉应用和备受瞩目的自然历史纪录片产生影响。

High contrast stripes are renowned for generating motion illusion in humans by altering the estimation of trajectory and speed oftargets. Striped patterns are also widespread in nature, from insects to mammals. Yet, there is still little experimental evidence aboutwhether, and how, animals evolved such patterns to dazzle, jam, or disrupt target visual systems. This project aims to collect the firstclear evidence supporting the use of motion dazzle in nature by investigating the effects of high contrast stripes in a real biologicalprey-predator interaction, the broadclub cuttlefish hunting crabs. This cuttlefish has a unique hunting technique. When approachingprey, it displays highly contrasting stripes moving in a downward direction across the head and arms. Our preliminary data not onlyshow that a greater contrast is required to elicit an escape response in crabs when an approaching stimulus features moving stripescompared to stationary stripes, but also that this effect depends on stripe speed. Implementation of motion detection algorithmsfurther suggests that crab responses may be altered by an overlaid downward motion cue very different from that expected by anapproaching predator, thus masking the looming cuttlefish. Using predator simulation experiments, tracking routines, andbiologically informed motion detection algorithms, the proposed research aims to 1) describe the effects of the hunting displayacross the full stimulus space and test if the natural hunting behaviour of the cuttlefish is optimised to interfere with crab vision; 2)determine the fine scale contexts under which the broadclub hunting display occurs; 3) reconstruct hunting sequences from crabvisual perspective and describe the optic flow patterns induced by the striped display on prey crabs. This research has the potential togenerate strong impact in the sensory biology community, with implications for machine vision applications and high-profile naturalhistory documentaries.