Behavioural responses of an Australian colubrid snake (Dendrelaphis punctulatus) to a novel toxic prey item (the Cane Toad Rhinella marina)
- 34 Downloads
The invasion of a toxic prey type can differentially affect closely related predator species. In Australia, the invasive Cane Toad (Rhinella marina) kills native anurophagous predators that cannot tolerate the toad’s toxins; but predators that are physiologically resistant (i.e., belong to lineages that entered Australia recently from Asia, where toads of other species are common) have been more resilient. In the current study, we examine the case of an Asian-derived predator lineage that relies on behavioural not physiological adaptations to deal with toads. Despite their Asian origins, Common Tree Snakes (Dendrelaphis punctulatus) are highly sensitive to toad toxins; yet this snake has not declined in abundance due to toads. We exposed captive (field-collected) snakes to toads of different sizes and ontogenetic stages, to quantify feeding responses and outcomes. Tree Snakes were less likely to attack toads than to attack native frogs, and rarely retained their hold on large toads. Tree Snakes ingested frogs of a wide range of body sizes but only ingested very small toads (< 1 g vs. up to 30 g for frogs). Behavioural responses were virtually identical between Tree Snakes from invaded versus yet-to-be-invaded areas, suggesting that preadaptation (from Asia) rather than adaptation (within Australia) is the key to successful utilisation of this novel but potentially toxic prey resource. Nonetheless, a previously-documented shift in relative head sizes of Tree Snakes coincident with toad invasion suggests that the ancestral behavioural tactic may have been reinforced by a recent morphological shift that further reduces maximal prey size, and hence the risk of fatal poisoning.
KeywordsAlien species Bufo marinus Evolution Predator–prey
We thank Brian West, Ian Eadie, Tanya Ross, Angus McNab, Bill Stewart and Justin Wright for their help collecting snakes, the James Cook University Animal Ethics Committee, and the University of Sydney Animal Care and Ethics Committee for approving all procedures.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
- Bowie JH, Wegener KL, Chia BC, Wabnitz PA, Carver JA, Tyler MJ, Wallace JC (1999) Host defence antibacterial peptides from skin secretions of Australian amphibians. The relationship between structure and activity. Protein Peptide Lett 6:259–270Google Scholar
- Cogger H (2014) Reptiles and amphibians of Australia, 7th edn. CSIRO Publishing, CollingwoodGoogle Scholar
- Covacevich J, Archer M (1975) The distribution of the cane toad, Bufo marinus in Australia and its effects on indigenous vertebrates. Mem Qld Mus 17:305–310Google Scholar
- Gosner KL (1960) A simplified table for staging anuran embryos and larvae with notes on identification. Herpetologica 16:183–190Google Scholar
- Greene HW (1988) Antipredator mechanisms in reptiles. In: Gans C (ed) Biology of the reptilia, vol 16. Alan R. Liss, New York, pp 1–152Google Scholar
- Lever C (2001) The cane toad. The history and ecology of a successful colonist. Westbury Academic and Scientific Publishing, OtleyGoogle Scholar
- Minton G, Das I (2012) Chrysopelea paradisi (Garden Flying Snake). Diet. Herpetol Rev 43:144Google Scholar
- Princy JL, Kannan P, Santhosh Kumar P, Samson A (2017) Predation of Raorchestes tinniens by Ahaetulla perroteti in Nilgiris, Tamil Nadu, India. Reptile Rap 169. Zoo’s Print 32:15–18Google Scholar
- Van Rooijen J, Vogel G, Somaweera R (2015) A revised taxonomy of the Australo-Papuan species of the colubrid genus Dendrelaphis (Serpentes: Colubridae). Salamandra 51:33–56Google Scholar
- Wells KD (2010) The ecology and behavior of amphibians. University of Chicago Press, ChicagoGoogle Scholar
- Wilson S, Swan G (2008) A complete guide to reptiles of Australia, 2nd edn. New Holland Publishers, SydneyGoogle Scholar