Recently, the Pryke Lab published its first paper on a reptile—the iconic Frillneck Lizard (Chlamydosaurus kingii). Both males and females have frills and until now, the consensus has always been that frills play a role in anti-predator behaviour. Not only does the frill startle a would-be predator, but it may also bluff them into thinking that their potential dinner might be dangerous and risky to catch. While this hypothesis still remains to be tested, Hamilton et al. explore an alternative hypothesis: that the frill might also play a role in sexual selection and signal fighting ability. They used optic spectrophotometry to objectively measure the colour of the frill and also measured a range of morphological and functional traits before size matching lizards in staged contests in neutral arenas. Surprisingly, traits such as frill size, head size and bite force did not predict contest outcome. Instead, males with brighter and more colourful frills were more likely to dominate opponents and take gold. They also took skin samples back to the lab to determine the source of pigments that generate the colour. Lab tests confirmed the presence of carotenoids which is an exciting result because while carotenoids have been the source of considerable study among birds, we know little about the role of carotenoids in lizards. This might be the first example of a carotenoid-based signal of fighting ability in a lizard. This is a must read study, very cool stuff!
To read more and download the paper check out Martin’s webpage and facebook post.
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