Beta diversity, prevalence, and specificity of avian haemosporidian parasites throughout the annual cycle of Chilean Elaenia (Elaenia chilensis), a Neotropical austral migrant

Abstract

Migratory birds are implicated in dispersing haemosporidian parasites over great geographic distances. However, their role in sharing these vector-transmitted blood parasites with resident avian host species along their migration flyway is not well understood. We studied avian haemosporidian parasites in 10 localities where Chilean Elaenia, a long-distance Neotropical austral migrant species, spends part of its annual cycle to determine local parasite transmission among resident sympatric host species in the elaenia's distributional range across South America. We sampled 371 Chilean Elaenias and 1,818 birds representing 243 additional sympatric species from Brazilian wintering grounds to Argentinian breeding grounds. The 23 haemosporidian lineages found in Chilean Elaenias exhibited considerable variation in distribution, specialization, and turnover across the 10 avian communities in South America. Parasite lineage dissimilarity increased with geographic distance, and infection probability by Parahaemoproteus decreased in localities harbouring a more diverse haemosporidian fauna. Furthermore, blood smears from migrating Chilean Elaenias and local resident avian host species did not contain infective stages of Leucocytozoon, suggesting that transmission did not take place in the Brazilian stopover site. Our analyses confirm that this Neotropical austral migrant connects avian host communities and transports haemosporidian parasites along its distributional range in South America. However, the lack of transmissive stages at stopover site and the infrequent parasite lineage sharing between migratory host populations and residents at breeding and wintering grounds suggest that Chilean Elaenias do not play a significant role in dispersing haemosporidian parasites, nor do they influence local transmission across South America.

Does host migration affect host-parasite interaction? Migrant birds harbor exclusive parasites but have similar roles in parasite-host networks.

“…Here, we observed that avian haemosporidians are specialized, infecting more commonly a speci c set of hosts. We also revealed specialization changes between distinct parasites, with Plasmodium lineages infecting a wider range of hosts than Haemoproteus (Fecchio et al 2022). When evaluating the ve more abundant species sampled in this study, we observed that all species present higher specialization and are infected by less distinct parasite lineages than expected, reinforcing the high degree of specialization observed when evaluating parasites.…”

Revealing the drivers of parasite community assembly: using avian haemosporidians to model global dynamics of parasite species turnover

“…This may explain the discrepancy between past research findings and the conclusions of the present study. Indeed, past research on large‐scale parasite turnover has confirmed this pattern among haemosporidians and other parasite taxa (Dallas and Poisot 2018, Fecchio et al 2019b, 2022, Martins et al 2021). Therefore, geographic distance might only play an important role in shaping parasite turnover at larger scales or when there is a higher degree of heterogeneity among sites, whereas landscape and host features are the most important factors determining parasite turnover at smaller scales or among more homogeneous environmental conditions.…”

“…Previous research has evaluated factors driving haemosporidian turnover at local and regional scales (Williamson et al 2019, McNew et al 2021, de La Torre et al 2022, Fecchio et al 2022). Some found that geographic distance was not the principal driver of parasite turnover.…”