Dazzled by shine: gloss as an antipredator strategy in fast moving prey

Animals with glossy surfaces are ubiquitous in nature, but why these striking appearances have evolved is unclear. We tested whether gloss provides protection from predators when prey are moving. Praying mantids were less likely to strike at moving targets that were glossy rather than matte, and were less likely to track and accurately strike glossy targets when they were moving fast. This study provides the first empirical evidence that gloss could offer protection against predation for fast moving animals. Previous studies on stationary prey have found mixed results for the role of a glossy appearance in predator avoidance-some have found that glossiness can act as warning coloration or improve camouflage, whereas others detected no survival benefit. An alternative untested hypothesis is that glossiness could provide protection in the form of dynamic dazzle. Fast moving animals that are glossy produce flashes of light that increase in frequency at higher speeds, which could make it harder for predators to track and accurately locate prey. We tested this hypothesis by presenting praying mantids with glossy or matte targets moving at slow and fast speed. Mantids were less likely to strike glossy targets, independently of speed. Additionally, mantids were less likely to track glossy targets and more likely to hit the target with one out of the two legs that struck rather than both raptorial legs, but only when targets were moving fast. These results support the hypothesis that a glossy appearance may have a function as an antipredator strategy by reducing the ability of predators to track and accurately target fast moving prey.

Automated summary

Animals with glossy surfaces may have evolved their appearance as a protection against predators when they are moving. Praying mantids were less likely to attack and accurately strike targets that were glossy and moving fast. This study provides empirical evidence that glossiness may offer protection for fast moving animals against predation.