Camouflage in a moving predator: testing for background choice in stalking lionfish ( <i>Pterois miles</i> )

Abstract Predation is pervasive in the natural world, where predators and prey have evolved spectacular mechanisms to avoid detection and recognition. An example is camouflage through background matching, which allows animals to resemble their background. Animals can move strategically towards backgrounds that match their morphology (background choice) to enhance camouflage. We studied the relevance of background choice in lionfish (Pterois miles), conspicuous stalking predators that could take advantage of background matching by resembling corals and other invertebrates in their surroundings. We offered different background combinations to hunting lionfish and we found that they indeed account for their background while hunting, although the response did not support the hypothesis that the preference is determined by background matching. Lionfish deviated towards a rocky background, which closely resembled the substrate where lionfish were caught (rocky reefs in the Mediterranean Sea). We suggest that lionfish showed a preference for a rocky background because in the Mediterranean they live on rocky reefs. While we cannot rule out that background matching played a role in background choice, we suggest that remaining close to a rocky reef while hunting offers lionfish the best combination of easy access to hiding spots and high availability of prey.