Host phylogeny matters: Examining sources of variation in infection risk by blood parasites across a tropical montane bird community in India

Abstract

Background Identifying patterns and drivers of infection risk among host communities is crucial to elucidate disease dynamics and predict infectious disease risk in wildlife populations. Blood parasites of the genera Plasmodium and Haemoproteus are a diverse group of vector-borne protozoan parasites that affect bird populations globally. Despite their widespread distribution and exceptional diversity, factors underlying haemosporidian infection risk in wild bird communities remain poorly understood. While some studies have examined variation in avian haemosporidian risk, researchers have primarily focused on host ecological traits without considering host phylogenetic relationships. In this study, we employ a phylogenetically informed approach to examine the association between host ecological traits and haemosporidian infection risk in endemic bird communities in the Western Ghats Sky Islands. Methods We used parasite sequence data based on partial mitochondrial cytochrome b gene, that was amplified from genomic DNA extracted from 1177 birds (28 species) across the Western Ghats to assess infection of birds with haemosporidian parasites. We employed a Bayesian phylogenetic mixed effect modelling approach to test whether haemosporidian infection risk was affected by seven species-specific and four individual-level ecological predictors. We also examined the effect of host phylogenetic relationships on the observed patterns of variation in haemosporidian infection risk by estimating phylogenetic signal. Results Our study shows that host ecological traits and host phylogeny differentially influence infection risk by Plasmodium (generalist parasite) and Haemoproteus (specialist parasite). For Plasmodium, we found that sociality, sexual dimorphism and foraging strata were important ecological predictors. For Haemoproteus, patterns of infection risk among host species were associated with sociality, species elevation and individual body condition. Interestingly, variance in infection risk explained by host phylogeny was higher for Haemoproteus parasites compared to Plasmodium. Conclusions Our study highlights that while host ecological traits promoting parasite exposure and host susceptibility are important determinants of infection risk, host phylogeny also contributes substantially to predicting patterns of haemosporidian infection risk in multi-host communities. Importantly, infection risk is driven by joint contributions of host ecology and host phylogeny and studying these effects together could increase our ability to better understand the drivers of infection risk and predict future disease threats. Graphical abstract

Host phylogeny and elevation predict infection by avian haemosporidians in a diverse New Guinean bird community

“…Our results add to accumulating evidence that host phylogeny is an important predictor of infection by avian haemosporidia. For example, phylogenetic relationship predicted infection prevalence better than environmental or ecological variables in a comparative dataset of Peruvian birds (Barrow et al, 2019), with similar results in recent studies from Colombia, India and Sweden (Ellis et al, 2020;Gupta et al, 2020;Pulgarín-R et al, 2018). There is also evidence that when parasites infect multiple hosts, parasites often use phylogenetically closely related hosts (Clark & Clegg, 2017): whether this is true in our system remains an open question.…”

“…In contrast, the primary vectors for Haemoproteus , the dominant parasite genus in our study system, are biting midges ( Culicoides sp ). The broader environmental tolerances of Haemoproteus vectors may explain why Haemoproteus infections in birds are often more common than infections by other haemosporidian genera at high elevations (González et al, 2014; Gupta et al, 2020; Rodríguez‐Hernández et al, 2021).…”

Global drivers of avian haemosporidian infections vary across zoogeographical regions

“…Haemosporidian parasites exhibit broad variation in prevalence, but the drivers of this variation across zoogeographical realms and among avian clades are only partially understood from region-level studies. In recent years, numerous studies have explored haemosporidian infection rates in birds across habitat gradients under different regional land-use or climate conditions, but with no consistent predictor identified across studies (e.g., Ellis et al, 2020;Gupta et al, 2020;Harvey & Voelker, 2019;Ishtiaq et al, 2017;Lutz et al, 2015;Santiago-Alarcon et al, 2019). Mounting evidence that various landscape and climate conditions, in addition to host and vector species attributes, might drive avian haemosporidian infections calls for global approaches to disentangle abiotic and biotic drivers and anticipate macroecological patterns of parasite spread under current and future conditions.…”

Correction to: Host phylogeny matters: Examining sources of variation in infection risk by blood parasites across a tropical montane bird community in India

“…Following publication of the original article [ 1 ], the authors flagged that the Conclusion of the article Abstract had been erroneously omitted from the PDF version of the article.…”