Female and male plumage colour signals aggression in a dichromatic tropical songbird. (April 2019)

• Record Type: Journal Article
• Authors: Leitão, Ana V.; Hall, Michelle L.; Delhey, Kaspar; Mulder, Raoul A.
• Is Part Of: Animal behaviour. Volume 150(2019)
• Page Start: 285
• Page End: 301
• Publication Date: 2019-04
• Subjects: badge of status -- colour manipulation -- competitive signals -- honest signalling -- Malurus -- mirror test -- social cost -- social punishment; Animal behavior -- Periodicals; 591.5
• DOI: 10.1016/j.anbehav.2019.01.025
• Languages: English
• ISSNs: 0003-3472

Abstract

Abstract : Animal signals of competitive ability allow contests for limited resources to be settled without costly physical fights. Traits indicating competitive ability are diverse and span visual, acoustic or chemical modalities. Although animal signalling has been intensively studied, research has focused mainly on male traits. Little is known about the extent and functionality of competitive signals in females and whether there are sex differences in signal function. We studied whether plumage colour signals competitive ability in female and male lovely fairy-wrens, Malurus amabilis. In this species, both sexes sport elaborate but sexually dichromatic ornamental plumage. Using a mirror image stimulation test, we first assessed the relationship between male and female colour and agonistic behaviour, controlling for other physical, social and ecological variables. We then tested whether colourful plumage influenced aggressive response in both sexes by experimentally manipulating plumage colour and measuring individual responses to their mirror image. Females and males were more aggressive towards naturally less colourful reflections of the cheek patch in the mirror. However, when we manipulated plumage colour, both females and males responded more aggressively to experimentally increased cheek colour reflection in the mirror. Our findings suggest that plumage colour signals competitive ability in an aggressive context in both sexes and raises the possibility that signal reliability may be maintained by social interactions where individuals police and punish dishonest signals. Highlights: Our understanding of female signals and sex differences is still limited. We used a mirror image test to study whether plumage colour signals aggression. Both sexes were more aggressive to natural, less colourful mirror reflections. Manipulated birds were more aggressive to increased colour reflections. Plumage colour of females and males appears to be used as a competitive signal.