Co-infection with Leucocytozoon and Other Haemosporidian Parasites Increases with Latitude and Altitude in New World Bird Communities

Establishing how environmental gradients and host ecology drive spatial variation in infection rates and diversity of pathogenic organisms is one of the central goals in disease ecology. Here, we identified the predictors of concomitant infection and lineage richness of blood parasites in New Word bird communities. Our multi-level Bayesian models revealed that higher latitudes and elevations played a determinant role in increasing the probability of a bird being co-infected with Leucocytozoon and other haemosporidian parasites. The heterogeneity in both single and co-infection rates was similarly driven by host attributes and temperature, with higher probabilities of infection in heavier migratory host species and at cooler localities. Latitude, elevation, host body mass, migratory behavior, and climate were also predictors of Leucocytozoon lineage richness across the New World avian communities, with decreasing parasite richness at higher elevations, rainy and warmer localities, and in heavier and resident host species. Increased parasite richness was found farther from the equator, confirming a reverse Latitudinal Diversity Gradient pattern for this parasite group. The increased rates of Leucocytozoon co-infection and lineage richness with increased latitude are in opposition with the pervasive assumption that pathogen infection rates and diversity are higher in tropical host communities.

Automated summary

This study aimed to understand the impact of environmental gradients and host ecology on infection rates and diversity of blood parasites in New World bird communities. The findings showed that higher latitudes and elevations increased the probability of birds being co-infected with Leucocytozoon and other haemosporidian parasites. Host attributes and temperature were also significant factors affecting infection rates, with heavier migratory hosts and cooler localities having higher probabilities of infection. Additionally, factors such as latitude, elevation, host body mass, migratory behavior, and climate influenced Leucocytozoon lineage richness, with decreasing richness at higher elevations, rainy and warmer localities, and in heavier and resident host species. The study challenged the assumption that pathogen infection rates and diversity are higher in tropical host communities.