After the crash: how do predators adjust following the invasion of a novel toxic prey type?

Llewelyn, John, Schwarzkopf, Lin, Phillips, Benjamin L., and Shine, Richard (2014) After the crash: how do predators adjust following the invasion of a novel toxic prey type? Austral Ecology, 39 (2). pp. 190-197.

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The ability of a native predator to adjust to a dangerously toxic invasive species is key to avoiding an ongoing suppression of the predator's population and the trophic cascade of effects that can result. Many species of anurophagous predators have suffered population declines due to the cane toad's (Rhinella marina: Bufonidae) invasion of Australia; these predators can be fatally poisoned from attempting to consume the toxic toad. We studied one such toad-vulnerable predator, the yellow-spotted monitor (Varanus panoptes: Varanidae), testing whether changes to the predator's feeding behaviour could explain how the species persists following toad invasion. Wild, free-roaming lizards from (1) toad-naïve and (2) toad-exposed populations were offered non-toxic native frogs and slightly toxic cane toads (with parotoid glands removed) in standardized feeding trials. Toad-naïve lizards readily consumed both frogs and toads, with some lizards displaying overt signs of illness after consuming toads. In contrast, lizards from toad-exposed populations consumed frogs but avoided toads. Repeated encounters with toads did not modify feeding responses by lizards from the toad-naïve populations, suggesting that aversion learning is limited (but may nonetheless occur). Our results suggest that this vulnerable predator can adjust to toad invasion by developing an aversion to feeding on the toxic invader, but it remains unclear as to whether the lizard's toad-aversion arises via adaptation or learning.

Item ID: 32063
Item Type: Article (Research - C1)
ISSN: 1442-9993
Keywords: aversion learning, Bufo marinus, ecological impact, rapid evolution, Varanidae
Date Deposited: 21 Mar 2014 01:08
FoR Codes: 05 ENVIRONMENTAL SCIENCES > 0502 Environmental Science and Management > 050202 Conservation and Biodiversity @ 100%
SEO Codes: 96 ENVIRONMENT > 9605 Ecosystem Assessment and Management > 960505 Ecosystem Assessment and Management of Forest and Woodlands Environments @ 100%
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