Rapid beard darkening predicts contest outcome, not copulation success, in bearded dragon lizards

Rapid colour change is widespread in animals and allows them to respond dynamically to the physical and social environment. However, few studies have examined the information conveyed by dynamic colour signals in different social contexts, such as courtship and rivalry contests. Furthermore, dynamic colour change on different body regions may be subject to different selection pressures and therefore serve different functions. We tested whether male colour or colour change predict contest outcome in male-male interactions, or the likelihood of copulation attempts in male-female interactions in the central bearded dragon, Pogona vitticeps. The extent of beard darkening strongly predicted contest outcome, but neither colour (beard, dorsal) nor colour change predicted copulation attempts. Dorsal colour showed little consistent change and did not predict contest outcome or copulation attempts. Previous work shows that dorsal but not beard colour change occurs in response to both background c...