Whiptail lizards (Aspidoscelis exsanguis) recognize invertebrate prey via cuticular hydrocarbons

Cuticular hydrocarbons (CHCs) present on the surface of arthropods are important mediators of both intraspecific and interspecific interactions. They are known to be important chemical cues that help predatory arthropods locate prey, yet less is known about if and how vertebrate insectivores use these nearly ubiquitous chemical cues. We examined behavioral responses of insectivorous lizards (Aspidoscelis exsanguis) to the CHCs of three different species of arthropod prey (crickets, ants, and spiders). We presented cotton swabs with either extracted CHCs or a solvent control to determine if lizards respond to CHCs in the absence of visual cues of prey. We found that CHCs not only increased the frequency of chemosensory behaviors performed by predatory lizards, but that they also elicit feeding‐like behavior from lizards (e.g., biting at the cotton swabs). These results indicate that lizards not only respond to arthropod CHCs, but that they are sufficient for prey‐recognition by our chosen lizard species. This finding lays the groundwork for future studies to investigate the precise compounds that are used by foraging lizards, and how the chemical communication systems of arthropods respond to selection exerted by vertebrate predators.

Methods
Dataset was collected from cotton swab presentation assays with captive wild-caught whiptail lizards at the Southwestern Research Station. All units are counts (# of observations during 5min trial) except for latencies, which are in seconds. A latency of 300 indicates that the behavior was not observed. Latency to escape behavior was not recorded during every trial due to human error. to.cue/to.sub/to.air/to.glass columns refer to tongue-flick behaviors and specify what the lizard made contact with during the behavior. Datasets are already in .csv format and ready to be used in the provided R scripts as they are.