What is it about?

Colour signals often play a crucial role in animal contests by allowing rivals to assess each other and adjust their investment in the fight accordingly. Here we show that contest outcome between males of the common wall lizard is associated with the relative size of their ventrolateral black patches. This is a necessary requisite for the black patches to act as colour signals, which should be explored in future manipulative experiments.

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Why is it important?

Animal contests can be lethal, but they rarely are. Understanding what limits aggression in nature remains a vibrant topic of research in ethology. One of the best supported hypothesis is that the costs of aggression are similar for winners and losers, and hence selection favors the evolution of colour signals allowing rivals to assess each other. Here we show that black melanin-based patches are associated with fighting ability, hence suggesting their possible role as agonistic signals. Interestingly, we did not find evidence for a role of UV-blue patches on male-male competition, which suggests that the black and UV-blue patches present in the complex ventrolateral colour pattern of lacertid lizards may convey different non-redundant information to receivers.


A positive correlation between dominance and melanin is recurrent in vertebrates. However, authors have often extrapoletd all too soon a possible signalling role (which requires further manipulative experiments to be warranted). By controlling for known determinants of contest outcome (i.e. size, prior experience, residency), we succeded in measuring the effect of colour signals, which may become obscured when lizards compete under more natural conditions. These results have implications for the fields of contest theory, animal communication, and sexual selection.

Javier Abalos
Lunds Universitet

Read the Original

This page is a summary of: The role of male coloration in the outcome of staged contests in the European common wall lizard (Podarcis muralis), Behaviour, January 2016, Brill, DOI: 10.1163/1568539x-00003366.
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