The role of pigment based plumage traits in resolving group conflicts (#815)
The role of melanin plumage, or ‘badges of
status’, in male-male competition has been well-studied. In contrast, carotenoid
based plumage has largely only been examined in the context of female mate
choice. Recent work has shown that carotenoid signals can also function in
male-male competition, though the relative importance of the two types of
signals is currently unclear. Here, we examine the relationships between
colouration, dominance and aggression in the crimson finch (Neochmia phaeton), a species where males
have both conspicuous red carotenoid plumage and a melanin black ‘badge’. We
examined the importance of carotenoid and melanin based signals in staged
dyadic contest in captivity. We found that carotenoid coloration was positively
related to the probability of winning a contest, while the size of the melanin
plumage patch was not related to contest outcome. When the carotenoid signal was
masked (plumage darkened) we found that the manipulated plumage colour was not
related to winning, while the underlying natural plumage colour was still
important, but birds with more carotenoids were now more likely to lose.
Nevertheless the number of interactions required to determine dominance
increased considerably. These results suggest that carotenoids are an important
signal in male-male contests but that they are used in conjunction with other
factors such as self-assessment and body condition. While the black melanin
patch, traditionally viewed as a signal of male dominance, was not found to be
important in this context.