Haemosporidian parasites and incubation period influence plumage coloration in tanagers (Passeriformes: Thraupidae)

Birds are visually oriented and use their plumage coloration as an important signaling trait in social communication. Males and females may have different patterns of plumage coloration, a phenomenon known as sexual dichromatism. Because males tend to have more complex plumages, sexual dichromatism is usually attributed to female choice. However, plumage coloration is partly condition-dependent, therefore other selective pressures affecting individuals’ success may also drive the evolution of this trait. Here we used tanagers to study the relationships between dichromatism and plumage coloration complexity with parasitism by haemosporidians, investment in reproduction, and life-history traits. We screened blood samples from 2849 birds belonging to 52 tanager species for detecting haemosporidian parasites. We used publicly available data for plumage coloration, bird phylogeny, and life-history traits to run models with plumage dichromatism and complexity in males and females. We found th...