What, if anything, does visual asymmetry in fallow deer antlers reveal?

Abstract

Fluctuating asymmetry (FA), small directionally random deviations from perfect bilateral symmetry, is thought to reflect individual quality. Furthermore, it has been suggested that FA in secondary sexual characters can be used to assess mate or opponent quality during inter- or intrasexual competition. Studies on fallow deer, Dama dama, have suggested that FA in antlers reflects individual dominance, or the existence of a directional asymmetry (DA) with right antlers being consistently more developed than left antlers. To test these conflicting hypotheses, we analysed relationships between age, dominance and asymmetry in the number of antler points on mature fallow deer males during four rutting seasons in a single population. Age and dominance were only weakly correlated. The number of antler points displayed a pattern of DA (more points on the right than on the left side) that increased with age. Although dominance tended to increase with the total number of antler points, there was no relationship between the level of DA and dominance. These results failed to support the hypothesis that antler asymmetry visually reveals individual quality in fallow deer.