Know Thine Enemy: Predator Identity Influences the Response of Western Banded Geckos (Coleonyx variegatus) to Chemosensory Cues
Most animals have predators, and therefore must balance the needs of foraging and mating with those of shelter and safety. Many species rely on chemosensory cues to identify predators and organize defenses specific to particular types of predators. A large body of research in this area has focused on lizards and snakes because they have heightened chemical senses and have been shown to identify predators using chemical cues alone. We designed an experiment to examine the antipredator behavior of a common desert-dwelling nocturnal lizard, the Banded Gecko (Coleonyx variegatus), towards snake predators that use different hunting techniques: active-hunting Glossy Snakes (Arizona elegans) and ambush-hunting rattlesnakes (Crotalus cerastes). We exposed Banded Geckos to chemical cues from these two predators and measured a series of behavioral responses including tail displays, time spent investigating chemical cues while actively moving, and time spent in refugia. Geckos exhibited clear antipredator behaviors toward both snakes but spent more time actively moving in response to glossy snake cues. Because rattlesnakes use ambush strategies to capture prey whereas glossy snakes are active searchers, remaining in place while assessing rattlesnake cues is probably less risky than when assessing glossy snake cues. Our findings indicate that Banded Geckos can not only discriminate among different predatory snake species based on chemical cues alone, but they also appear to adjust their antipredator responses in a predator-specific manner.ABSTRACT

Geckos exposed to snake chemical cues exhibited more tail displays than those in the control condition, but there was no significant difference in tail displays between the two snake treatments. Box and whiskers indicate quartiles, and open circles indicate outliers.

With no predator scent present, geckos typically moved promptly under the shelter object, where they spent the majority of the 600-sec trial period. In the presence of chemical cues from either snake, geckos spent more time exploring the arena and significantly less time sheltering. The difference in shelter time between the snake treatments was not significant. Box and whiskers indicate quartiles, and open circles indicate outliers.

While exploring the arena, geckos exposed to snake chemical cues spent significantly more time freezing in place compared to control conditions. Geckos also spent more time freezing in place and less time actively moving when in the presence of chemical cues from sidewinder rattlesnakes than when in the presence of chemical cues from glossy snakes. Box and whiskers indicate quartiles, and open circles indicate outliers.
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