Tracking the assembly of nested parasite communities: Using β‐diversity to understand variation in parasite richness and composition over time and scale

Abstract

1. Community composition is driven by a few key assembly processes: ecological selection, drift and dispersal. Nested parasite communities represent a powerful study system for understanding the relative importance of these processes and their relationship with biological scale. Quantifying β-diversity across scales and over time additionally offers mechanistic insights into the ecological processes shaping the distributions of parasites and therefore infectious disease.2. To examine factors driving parasite community composition, we quantified the parasite communities of 959 amphibian hosts representing two species (the Pacific chorus frog, Pseudacris regilla and the California newt, Taricha torosa) sampled over 3 months from 10 ponds in California. Using additive partitioning, we estimated how much of regional parasite richness (γ-diversity) was composed of within-host parasite richness (α-diversity) and turnover (β-diversity) at three biological scales: across host individuals, across species and across habitat patches (ponds). We also examined how β-diversity varied across time at each biological scale.3. Differences among ponds comprised the majority (40%) of regional parasite diversity, followed by differences among host species (23%) and among host individuals (12%). Host species supported parasite communities that were less similar than expected by null models, consistent with ecological selection, although these differences lessened through time, likely due to high dispersal rates of infectious stages. Host individuals within the same population supported more similar parasite communities than expected, suggesting that host heterogeneity did not strongly impact parasite community composition and that dispersal was high at the individual host-level. Despite the small population sizes of within-host parasite communities, drift appeared to play a minimal role in structuring community composition. 4. Dispersal and ecological selection appear to jointly drive parasite community assembly, particularly at larger biological scales. The dispersal ability of aquatic parasites with complex life cycles differs strongly across scales, meaning that parasite communities may predictably converge at small scales where dispersal is high, but may be more stochastic and unpredictable at larger scales. Insights into assembly mechanisms within multi-host, multi-parasite systems provide opportunities for understanding how to mitigate the spread of infectious diseases within human and wildlife hosts. Additional supporting information may be found online in the Supporting Information section. How to cite this article: Moss WE, McDevitt-Galles T, Calhoun DM, Johnson PTJ. Tracking the assembly of nested parasite communities: Using β-diversity to understand variation in parasite richness and composition over time and scale. J Anim

Community structure of intestinal adult trematodes (Platyhelminthes) in six species of Haemulon (Osteichthyes) in Puerto Morelos Reef National Park, Quintana Roo, Mexico

“…Furthermore, trematode communities differed among species of grunts, indicating that ecological factors such as feeding habits, geographic distribution, and vagility of the hosts play a major role structuring these communities. In general, our results are consistent with several studies that indicate that ecological selection can strongly structure parasite communities (Moos et. al., 2020).…”

“…Moreover, patterns of similarity were very similar at both scale levels of our study; this indicates a low beta diversity which can be the result of high dispersion rates (vagility), which acts to homogenize communities (Moos et al, 2020). At the infracommunity level, a low exchange of trematode species was shown, indicating that not all the species occur in all individual hosts; meanwhile, the b-diversity of the component community, despite being low, presented some species that are shared among host species, e.g., L. decora and H. mutabile, as well as other species that exhibited some level of host specificity for some of species of Haemulon; that is the case for Homalometron.…”

Abundance data applied to a novel model invertebrate host shed new light on parasite community assembly in nature

“…As all parasite community data trends (among host species or sites) are driven by infracommunity‐level interactions (Bush et al., 1997; Pederson & Fenton, 2007), understanding influences on infracommunity structure is key to the study of parasite community ecology. However, there is still little research with this focus (but see Moss et al., 2020; Pilosof et al., 2015).…”

Scale‐dependent effects of host patch traits on species composition in a stickleback parasite metacommunity

“…Different host populations may inhabit substantially divergent abiotic and biotic settings, giving rise to large differences in parasite colonization and persistence. Abiotic conditions (temperature, elevation, salinity) differ across a landscape and play a major role in structuring among‐host‐population parasite communities (Ebert et al 2001, Richgels et al 2013, Dallas and Presley 2014, Cirtwill et al 2016, Moss et al 2020). For example, the cestode S. solidus fails to hatch in brackish water, and so is unique to freshwater rather than marine stickleback.…”