Avian haemosporidian and latitudinal gradients: Opportunities and challenges in the Southern Cone of America

Abstract

Latitudinal diversity gradients (LDG) explain the distribution and species richness in free-living organisms of multiple taxa, where richness increases toward low latitudes. However, parasites have shown inconsistencies to this spatial pattern. In the case of avian haemosporidians (Plasmodium, Haemoproteus and Leucocytozoon), they have shown differences depending of the genera and geographic scale. Thus, at global scale none of the three genera presents a latitudinal gradient of diversity. In South America, Plasmodium and Haemoproteus present a LDG, and the prevalence shows the same pattern in local Chile. In contrast, Leucocytozoon exhibits an inverse latitudinal pattern at the continental level and in Chile, where diversity and prevalence are associated with high latitudes. The climatic and habitat characteristics of the Amazon represents great influence to maintain the interactions of Plasmodium and Haemoproteus with their vectors and hosts but represent an environmental filter for Leucocytozoon. Despite the important role of vectors in the maintenance of LDG for avian haemosporidians, this approach has not been incorporated in any study in the region. Finally, biogeographic barriers, such as the Andes mountain range could interrupt the dispersal of lineages from the Amazon to other regions, like the Southern Cone of America. Thus, countries such as Chile and Argentina present extraordinary geographical characteristics to explore hypotheses associated with local dispersion and/or diversification processes.