Drivers of fish parasite infracommunities in a high latitude system – a dive into host and parasite traits shaping parasite diversity

Abstract

Understanding the structuring drivers of host-parasite communities is central to predicting how these organisms will respond to environmental changes that are occurring at a rapid rate in northern latitude systems. Many factors shaping complex and ecologically important communities of fish-parasites in freshwater systems remain incompletely understood, particularly at the infracommunity level. Using multivariate analyses, this study aims to identify how the functional traits of both hosts (diet and sex) and parasites (transmission strategies) can influence parasite community structure. Five sympatric fish species (Alburnus alburnus, Esox lucius, Gymnocephalus cernua, Perca fluviatilis, Rutilus rutilus) were sampled in the Glomma River in Norway and their metazoan parasite communities (helminths, crustacea, bivalves, hirudinea) were identified. No clear hierarchical pattern in the species richness of trophically or actively transmitted parasites was detected, but host diet structured parasite community composition, separating piscivorous, benthivorous and planktivorous fish. Host sex on the other hand did not appear to shape parasite communities in the five fish species. Overall, my results show that functional traits are important to include in the study of host-parasite communities, as they can provide insights into the ecological interaction between these organisms.