1. Female ornamentation in European serins is related to age but not to male mate choice and social competition.
- Author
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Trigo, Sandra, Leitão, Ana V., Ferreira, André C., and Mota, Paulo Gama
- Abstract
Sexual selection theory has provided explanation for the evolution and function of elaborate male traits, yet less effective in explaining female trait expression. Consequently, there remains a significant gap in our understanding of how female ornamentation is maintained and what factors drive its evolution. The European serin (Serinus serinus) displays a dichromatic carotenoid-based plumage, with a yellow patch on the breast in both males and females, although with females displaying less conspicuous colouration. While yellow colouration in male serins serves a dual function in social contexts, both sexual and nonsexual, the potential signal role of this colouration in females remains unknown. This study investigates the relationship between female traits, measures of fitness and the potential sexual and social function of female plumage colouration. To achieve this, we conducted a male mate choice experiment and a social competition experiment for access to limited food, similar to those previously employed with male serins. We found a relation between yellow plumage colouration and age classes, with older females displaying more colourful plumage. The mate choice experiment did not reveal a male sexual preference based on carotenoid-based plumage colouration in females. Furthermore, while females established steep hierarchies within groups, dominance over food was not associated with plumage colour. These findings suggest that in the European serin, female plumage may be subject to direct natural selection for less conspicuous colours or may result from genetic correlation of a male-selected trait. Significance statement: Understanding of factors influencing the expression of female traits remains limited. This study addresses this knowledge gap by investigating the putative sexual and social functions of female plumage coloration in the European serin, a species displaying dichromatic carotenoid-based plumage. Our findings reveal a correlation between carotenoid-based yellow plumage coloration and age classes in females, indicating potential age-related changes in ornamental traits. We found no evidence of male preference for female plumage coloration, nor association with resource dominance. We discuss potential mechanisms driving the maintenance of these traits, such as natural selection favouring less conspicuous colours, or genetic correlations with male-selected traits. These findings contribute to our understanding of the complex mechanisms shaping sexual dimorphism. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
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