John Llewelyn

Although I am interested in many aspects of biology, I am especially fascinated by herpetology and evolutionary biology. My interest in these two areas has led me to study the relationship between cane toads and amphibian-eating reptiles in North Queensland (Australia) for my PhD.

Most native reptiles die if they consume a cane toad. It is not surprising then that populations of many amphibian-consuming reptiles have been observed/reported to decline rapidly following cane toad invasion. However, many native species that are initially affected by cane toad invasion have managed to survive, and often thrive, in North Queensland despite the presence of cane toads for over 60 years. The persistence and success of these native species in this region suggests that these species can adjust to the presence of cane toads through learning and/or adaptation.

I have only recently begun my PhD and I am currently planning my research. As a result of the above observations, the general question I will be addressing is: How have amphibian-consuming reptiles managed to survive in sympatry with cane toads in North Queensland? To answer this I will be studying various common amphibian-consuming reptiles such as the Australian keelback snake (Tropidonophis mairii, pictured above ), the common tree snake (Dendrelaphis punctulatus, pictured left), the brown tree snake (Boiga irregularis) and Varanus panoptes. My experiments will test if amphibian-consuming reptiles can differentiate between cane toads and native frogs, the cues used to differentiate these two prey groups and whether the ability to differentiate toads and native frogs is a learnt behaviour or a hard-wired trait.

The results of my research will improve our understanding of the long term impact of cane toads on native predators and will have applications in conservation strategies and prioritization.

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1999-2003	Bachelor of Science with 1st Class Honours, University of Sydney
2004	Certificate IV in Assessment and Workplace Training, TAFE NSW
2004-2005	Dilpoma in Education, University of New England
2006-	PhD student, University of Sydney

1.	Llewelyn, J., R. Shine and J.K. Webb. 2005. Thermal regimes and diel activity patterns of four species of small elapid snakes from southeastern Australia. Australian Journal of Zoology 53:1-8.
2.	Llewelyn, J., R. Shine and J.K. Webb. 2006. Time of testing affects locomotor performance in nocturnal versus diurnal snakes. Journal of Thermal Biology 31:268-273.
3.	Llewelyn, J., B. L. Phillips, and R. Shine. 2008. Sublethal costs associated with the consumption of toxic prey by snakes. Austral Ecology: in press.