title: Eliciting conditioned taste aversion in lizards: Live toxic prey are more effective than scent and taste cues alone.
abstract: Conditioned taste aversion (CTA) is an adaptive learning mechanism whereby a consumer associates the taste of a certain food with symptoms caused by a toxic substance, and thereafter avoids eating that type of food. Recently, wildlife researchers have employed CTA to discourage native fauna from ingesting toxic cane toads (Rhinella marina), a species that is invading tropical Australia. In this paper, we compare the results of 2 sets of CTA trials on large varanid lizards ("goannas," Varanus panoptes). One set of trials (described in this paper) exposed recently-captured lizards to sausages made from cane toad flesh, laced with a nausea-inducing chemical (lithium chloride) to reinforce the aversion response. The other trials (in a recently-published paper, reviewed herein) exposed free-ranging lizards to live juvenile cane toads. The effectiveness of the training was judged by how long a lizard survived in the wild before it was killed (fatally poisoned) by a cane toad. Both stimuli elicited rapid aversion to live toads, but the CTA response did not enhance survival rates of the sausage-trained goannas after they were released into the wild. In contrast, the goannas exposed to live juvenile toads exhibited higher long-term survival rates than did untrained conspecifics. Our results suggest that although it is relatively easy to elicit short-term aversion to toad cues in goannas, a biologically realistic stimulus (live toads, encountered by free-ranging predators) is most effective at buffering these reptiles from the impact of invasive toxic prey.
authors: School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales, Australia.
authors: Georgia
authors: G
authors: Ward-Fear
authors: School of Veterinary and Life Sciences, Murdoch University, Western Australia, Australia.
authors: Jai
authors: J
authors: Thomas
authors: School of Life Sciences, University of Technology Sydney, Broadway, New South Wales, Australia.
authors: Jonathan K
authors: JK
authors: Webb
authors: Western Australian Department of Parks and Wildlife, Waneroo, Western Australia, Australia.
authors: David J
authors: DJ
authors: Pearson
authors: School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales, Australia.
authors: Richard
authors: R
authors: Shine
mesh_terms: D000818:Animals; D001362:Avoidance Learning; D002024:Bufo marinus; D003463:Cues; D058865:Introduced Species; D018021:Lithium Chloride; D008116:Lizards / Q000502:physiology*; D009812:Odorants; D011235:Predatory Behavior; D013649:Taste; D014118:Toxins, Biological / Q000633:toxicity*; D014904:Western Australia
chemical_list: D014118:Toxins, Biological; D018021:Lithium Chloride
keywords: Rhinella marina; Varanus; conditioned taste aversion; conservation; invasive species; tropical Australia