Host Traits and Avian Malaria Parasites: Understanding the Intrinsic Connections

Parasitism can play a key role in shaping species' adaptability to environmental changes. Understanding how intrinsic traits of bird species influence susceptibility to haemosporidian infection is critical for understanding host-parasite dynamics, especially in biodiverse tropical regions. This study aimed to determine the host traits that influence the probability of haemosporidian infection in birds in a tropical country. We compiled published haemosporidian diagnoses of birds from Colombia and data on ecological, morphological, coloration, and sexual selection (dimorphism and dichromatism) traits. We also calculated an index for habitat specialization. Using phylogenetic generalized linear models (phylo-GLMs), we performed a phylogenetically informed comparative analysis of 115 bird species from different families with diverse characteristics. Our analysis revealed that migratory species, birds with larger body sizes, and those with more colorful plumage had a higher probability of infection. Conversely, habitat specialization was negatively associated with infection risk. Our results are explained in the framework of increased exposure to haemosporidian vectors. However, further studies are needed to better understand the relationship between the traits related to sexual selection and infection. These findings provide valuable insights into host-parasite dynamics in tropical bird communities and help to understand susceptibility factors, considering the potential negative consequences for avian communities.