Male competition is a driving force in the evolution and exaggeration of male traits and colourful male badges are a striking example of this. Ultraviolet (UV) colour badges are an interesting example of colourful signals that while invisible to us are used extensively in a range of other taxa, including lizards, birds and insects. We investigated how UV signals were used during male contests in the Augrabies flat lizard. These brightly coloured, highly territorial males fight over small territories on the edge of the Orange River in North West South Africa. The males use a sterotypical “ventral display” to signal to other males, which reveals their ventral colour patch and inflated throat (video of lizards in action). Work in Martin’s Lab has shown that ultraviolet (UV) reflectance of the throat was related to a male’s contest success. We used a field manipulation study to investigate how a reduction in throat UV influenced contest escalation and contest outcome in territorial and floater males. The study revealed that throat UV played a pivotal role in male assessment, males with reduced throat UV were challenged more often and engaged in more escalated contests. However, the outcome of the contest was not influenced by a reduction in throat UV.
The postdoc is jointly funded by the University of Witswatersrand and the National Research Foundation.
Stapley J and Whiting MJ. (2006) UV signals fighting ability in a lizard. Biology Letters 2: 169-172 (pdf).
M0re photos from Augrabies South Africa.