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

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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.