Data from: Abundance data applied to a novel model invertebrate host sheds new light on parasite community assembly in nature

Understanding how environmental drivers influence the assembly of parasite
communities, in addition to how parasites may interact at an
infracommunity level, are fundamental requirements for the study of
parasite ecology. Knowledge of how parasite communities are assembled will
help to predict the risk of parasitism for hosts, and model how parasite
communities may change under variable conditions. However, studies
frequently rely on presence-absence data and examine multiple host species
or sites, metrics which may be too coarse to characterise nuanced
within-host patterns. We utilised a novel host system, the freshwater
mussel Anodonta anatina, to investigate the drivers of community structure
and explore parasite interactions. In addition, we aimed to highlight
consistencies and inconsistencies between presence-absence and abundance
data. Our analysis incorporated 14 parasite taxa and 720 replicate
infracommunities. Using redundancy analysis, a joint species distribution
model and a Markov random fields approach, we modelled the impact of both
host-level and environment-level characteristics on parasite structure, as
well as parasite-parasite correlations after accounting for all other
factors. This approach was repeated for both the presence and abundance of
all parasites. We demonstrated that the regional species pool, individual
host characteristics (mussel length and gravidity) and predicted
parasite-parasite interactions are all important but to varying degrees
across parasite species, suggesting that applying generalities to parasite
community construction is too simplistic. Further, we showed that
presence-absence data fails to capture important density-dependent effects
of parasite load for parasites with high abundance, and in general
performs poorly for high-intensity parasites. Host and parasite traits, as
well as broader environmental factors, all contribute to parasite
community structure, emphasising that an integrated approach is required
to study community assembly. However, care must be taken with the data
used to infer patterns, as presence-absence data may lead to incorrect
ecological inference.