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

Abstract

Why do some regions share more or fewer species than others? Community assembly relies on the ability of individuals to disperse, colonize and thrive in new regions. Therefore, many distinct factors, such as geographic distance and environmental features, can determine the odds of a species colonizing a new environment. For parasites, host community composition (i.e. resources) also plays a key role in their ability to colonize a new environment as they rely on their hosts to complete their life cycle. Thus, variation in host community composition and environmental conditions should determine parasite turnover among regions. Here, we explored the global drivers of parasite turnover using avian malaria and malaria‐like (haemosporidian) parasites. We compiled global databases on avian haemosporidian lineages distributions, environmental conditions, avian species distributions and functional traits, and ran generalized dissimilarity models to uncover the main drivers of parasite turnover. We demonstrated that haemosporidian parasite turnover is mainly driven by geographic distance followed by host functional traits, environmental conditions and host distributions. The main host functional traits associated with high parasite turnover were the predominance of resident (i.e. non‐migratory) species and strong territoriality, while the most important climatic drivers of haemosporidian turnover were mean temperature and temperature seasonality. Overall, we established the importance of geographic distance as a key predictor of ecological dissimilarity and showed that host resources influence parasite turnover more strongly than environmental conditions. We also evidenced that parasite turnover is most pronounced among tropical and less interconnected regions (i.e. regions with mostly territorial and non‐migratory hosts). Our findings provide a robust foundation for the prediction of avian pathogen spread and the emergence of infectious diseases.

Network specificity decreases community stability and competition among avian haemosporidian parasites and their hosts

“…We acknowledge that the area covered by a 5X5 degrees cell encompasses diverse habitats and that not all bird species will occupy the entire cell; thus, it is at the upper end of what may be considered a community. The use of geographical grids to delimit communities is consistent with previous studies on avian haemosporidian parasites (de Angeli Dutra et al., 2023) and well established in ecology (Bousquin, 2021; Rangel et al., 2018).…”

“…As a result, climate might have important bottom‐up effects by driving parasite competition (Albrecht et al., 2018). At the same time, seasonality is also linked to higher turnover and diversity of haemosporidians (de Angeli Dutra, 2023; de Angeli Dutra et al., 2023) and could affect vector diversity and abundance (Gray & Ogden, 2021; Kelly‐Hope et al., 2009; Li et al., 2021). This suggests that environmental specialization might occur in regions with high seasonality, a phenomenon that might have emerged as a mechanism to decrease competition in harsher environments.…”

High prevalence of haemosporidian parasites in Eurasian Jays

“…However, how exactly phylogenetic, climatic, environmental and behavioural factors influence and form the occurrence and distribution of haemosporidian parasites is still under research (e.g. Pigeault et al 2022;de Angeli Dutra et al 2023).…”

Assessing global drivers of parasite diversity: host diversity and body mass boost avian haemosporidian diversity

“…For instance, de Angeli Dutra et al . ( 2023 ) demonstrated temperature variations were the main climatic driver of haemosporidian turnover. Therefore, climate should affect haemosporidian composition without enhancing parasite diversification.…”