Climate, host phylogeny and the connectivity of host communities govern regional parasite assembly

Abstract

Aim: Identifying barriers that govern parasite community assembly and parasite invasion risk is critical to understand how shifting host ranges impact disease emergence.We studied regional variation in the phylogenetic compositions of bird species and their blood parasites (Plasmodium and Haemoproteus spp.) to identify barriers that shape parasite community assembly.Location: Australasia and Oceania. Methods:We used a data set of parasite infections from >10,000 host individuals sampled across 29 bioregions. Hierarchical models and matrix regressions were used to assess the relative influences of interspecies (host community connectivity and local phylogenetic distinctiveness), climate and geographic barriers on parasite local distinctiveness and composition.Results: Parasites were more locally distinct (co-occurred with distantly related parasites) when infecting locally distinct hosts, but less distinct (co-occurred with closely related parasites) in areas with increased host diversity and community connectivity (a proxy for parasite dispersal potential). Turnover and the phylogenetic symmetry of parasite communities were jointly driven by host turnover, climate similarity and geographic distance. Main conclusions:Interspecies barriers linked to host phylogeny and dispersal shape parasite assembly, perhaps by limiting parasite establishment or local diversification.Infecting hosts that co-occur with few related species decreases a parasite's likelihood of encountering related competitors, perhaps increasing invasion potential but decreasing diversification opportunity. While climate partially constrains parasite distributions, future host range expansions that spread distinct parasites and diminish barriers to host shifting will likely be key drivers of parasite invasions. K E Y W O R D Scommunity assembly, host shifting, host specificity, interspecies barriers, parasite invasion, Plasmodium

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

“…Blackflies have been shown to harbour high diversities of Leucocytozoon parasites within a single species (Murdock, Adler, Frank, & Perkins, ), supporting the idea that vectors may play important roles in facilitating transmission of Leucocytozoon infections across distantly related bird species. Furthermore, many parasites and pathogens can infect unrelated host species with similar ecological niches, such as habitat use, nesting behaviour and diet (Clark et al, ; Poulin, ). Whereas these host traits are often phylogenetically conserved, they may also be influenced by environmental conditions.…”

“…For each of the 69 sampling sites in our dataset, we extracted altitude as well as several long‐term climate variables that could relate to Leucocytozoon infection prevalence by influencing the distributions and densities of vectors (see Appendix S1). Previous studies have found evidence that temperature and precipitation variables, particularly those that capture variation in summer and winter climates, may be linked to important aspects of haemosporidian community assembly and transmission (Clark et al, ; Fecchio, Wells, et al, ; Oakgrove et al, ; Sehgal et al, ). We included maximum temperature of the warmest month, maximum rainfall of the wettest month, minimum temperature of the coldest month and minimum rainfall of the driest month as predictors in our analysis.…”

Avian host composition, local speciation and dispersal drive the regional assembly of avian malaria parasites in South American birds

“…These haemosporidian parasites are globally distributed and diverse in most bird families (Valkiūnas, ; Clark, Clegg, & Lima, ). The ability of these bird parasites to disperse geographically and to shift among avian hosts has played a significant role in their diversification and distribution (Ellis et al, ; Clark et al, ; Fecchio et al, ). However, few empirical studies have assessed how avian haemosporidian diversity and distributions differ across biogeographical regions and latitudinal gradients (Clark et al, ; Clark, ).…”

The dynamics of preferential host switching: Host phylogeny as a key predictor of parasite distribution*

“…This means that both geographical range overlap and ecological interactions between donor and potential recipient host species may be important determinants of host shifts (e.g., Clark et al. ). Finally, de Vienne et al.…”