Evolution of sexual dichromatism in the "Blue" cardinalids (Passeriformes: Cardinalinos).

TUBARO, P. L.; GARCIA, N. C,; BARREIRA, A. S.

Puerto Iguazú, Misiones

Congreso; Ornithological Congress of the Americas - XVII RAO - XXIV CBO - XCV AFO; 2017

Association of Field Ornithologists - Aves Argentinas - Sociedad Brasilia de Ornitología

Sexual dichromatism in birds is assumed to be the product of sexual selection on males and/or of natural selection on females. However, there are other factors rarely considered that could have affected the evolution of differences in plumage color between males and females. Recently a negative relationship between dichromatism and body size was reported for passeriforms: both males and females of larger species tend to be more colorful but less dichromatic. Additionally, since most of the genome is shared between males and females, the increase or reduction of elaboration in the plumage of one sex can lead to changes in the other sex. However, it has never been explored if the positive correlation between plumage elaboration of males and females is affected by the mechanism responsible of plumage coloration (i.e. pigments such as carotenoids or melanins, or the feather nano-structure). Here we explore the relationship of sexual dichromatism with body size and color production mechanism among 13 species of the Cardinalidae family (the "blue" cardinalids). Contrary to previous results, sexual dichromatism was not related to male plumage elaboration, but correlated positively with body size. We also found an effect of the presence of carotenoids in the relationship between males and females color elaboration. These results add evidence on the relationship of body size and coloration, and show for the first time that color mechanism may influence the degree of sexual differentiation in plumage color.