Elicitation of Brown Treesnake Predatory Behavior Using Polymodal Stimuli

The brown treesnake (Boiga irregularis) is a species of special management concern, requiring improvement of capture methods through the development of effective artificial lures. Toward this end, we used night-vision cameras and mechanical models to study the interplay of sensory modalities for stimulating predatory behavior in brown treesnakes. Snakes oriented toward live mouse (Mus musculus) lures in complete darkness as much as they did to live mice lures under visible-light illumination; however, brown treesnakes in an unlighted environment responded qualitatively differently by probing and biting at the lure holder rather than striking at the mouse within (as did snakes in lighted trials). We altered the odors and vibratory cues of mechanical models to partition attractive stimuli and to measure snake response to vibratory cues. Fur-covered odorized (by rubbing with freshly defrosted dead neonatal mouse) models were more attractive than fur-covered non-odorized models, odor alone, and empty lure holders. Brown treesnake response to live mice did not differ from their response to smooth, odorized models, and moving versions of the smooth, odorized models stimulated more predatory behavior than unmoving models. Response from brown treesnakes appears to increase as odor and mechanical vibration stimuli are increased quantitatively and-or qualitatively. Conceptually, we hypothesize that polymodal stimuli synergize to promote predatory behavior in foraging snakes and that for trapping purposes, a multi-sensory attractant, optimized at each modality will be required to achieve capture success similar to or better than that obtained using live mice lures.