Deeply conserved susceptibility in a multi-host, multi-parasite system

Abstract

Variation in susceptibility is ubiquitous in multi‐host, multi‐parasite assemblages, and can have profound implications for ecology and evolution in these systems. The extent to which susceptibility to parasites is phylogenetically conserved among hosts can be revealed by analysing diverse regional communities. We screened for haemosporidian parasites in 3983 birds representing 40 families and 523 species, spanning ~ 4500 m elevation in the tropical Andes. To quantify the influence of host phylogeny on infection status, we applied Bayesian phylogenetic multilevel models that included a suite of environmental, spatial, temporal, life history and ecological predictors. We found evidence of deeply conserved susceptibility across the avian tree; host phylogeny explained substantial variation in infection status, and results were robust to phylogenetic uncertainty. Our study suggests that susceptibility is governed, in part, by conserved, latent aspects of anti‐parasite defence. This demonstrates the importance of deep phylogeny for understanding present‐day ecological interactions.

An inverse latitudinal gradient in infection probability and phylogenetic diversity for Leucocytozoon blood parasites in New World birds

“…Contrary to previous studies demonstrating an increase of prevalence with increasing elevation across the tropical Andes (Barrow et al, ; Galen & Witt, ; González et al, ; Harrigan et al, ; Lotta et al, ), we have shown no effect of altitude on infection probability and phylogenetic diversity of Leucocytozoon across bird communities at a continental scale. This pattern may be driven by the scarcity of Leucocytozoon infections in the highland Atlantic Forest and the moderate prevalence of Leucocytozoo n in some low‐elevation sites such as the Pantanal and temperate forest.…”

“…We used these host traits because they are known to influence haemosporidian diversity and prevalence and are available in open‐source data repositories. The predicted effects of these traits specifically on Leucocytozoon infection have been debated previously (Barrow et al, ; Lutz et al, ). As sex information was missing for 1,424 birds, we imputed these missing values using Bernoulli draws with a prior belief of p = .5.…”

“…Fecchio et al () linked the scarcity of Leucocytozoon infections with warmer temperatures in the tropical lowlands rather than a lack of transmission opportunity, as the vectors for this genus (black flies in the family Simuliidae) are abundant and diverse in lowland regions. Nevertheless, some studies have found strong support for the relationship between prevalence of Leucocytozoon and altitude (Barrow et al, ; Galen & Witt, ; González et al, ; Harrigan et al, ; Lotta et al, ) or latitude (Merino et al, ). However, the combined effect of latitude and altitude that ultimately reflects a gradient of temperature, precipitation and host diversity have never been tested for Leucocytozoon infections across the New World (but see Barrow et al, for a local analysis across the Tropical Andes of Peru).…”

Detecting turnover among complex communities using null models: A case study with sky-island haemosporidian parasites

“…Nuthatches also had very low prevalence; we did detect infections in five of 80 birds (6.25%) by PCR, but found no gametocytes in thin blood smears, suggesting that these might represent abortive infections of atypical hosts (Olias et al 2011; Moens et al 2016). At the clade level, suboscines were the least infected, a pattern that has been demonstrated consistently and has been used to illustrate that susceptibility to haemosporidians is evolutionarily conserved (Ricklefs 1992; Barrow et al 2019). Corvides was the most infected host clade, with 58 of 78 birds (74%) infected and a total of 97 infections detected.…”

Robust geographical determinants of infection prevalence and a contrasting latitudinal diversity gradient for haemosporidian parasites in Western Palearctic birds

“…Both variables were obtained at 10 × 10 km resolution using the MODISTools R package (Tuck et al., 2014) and included as mean values, averaged across months when peak haemosporidian transmission is likely to occur in our study region: May–August. Finally, we included elevation (meters above sea level) as a predictor based on previous evidence that high‐elevation environments show increased prevalence of Leucocytozoon parasites (Barrow et al., 2019; Galen & Witt, 2014). Elevation for each site was extracted from Amazon Web Services (https://registry.opendata.aws/terrain-tiles/) using functions in the elevatr r package (Hollister & Shah, 2017).…”