SEASONAL SUCCESSION OF CESTODE METACOMMUNITIES IN MUSEUM COLLECTIONS OF TWO NORTH AMERICAN SHREWS (SOREX SPP.).

Seasonal patterns in parasite diversity and prevalence are determined by a suite of factors ranging from environmental conditions (e.g., temperature, precipitation) to host behavior and traits. The forces shaping these patterns are increasingly unstable due to anthropogenic climate change, emphasizing the importance of leveraging natural history collections to understand how historical environmental conditions contributed to the spatiotemporal distributions of parasites and parasitic diseases. We implemented frameworks from metacommunity analyses to test for seasonal trends in parasite community structure attributable to host and abiotic environment in 2 North American shrew species, Sorex cinereus and Sorex monticola. Shrews were collected using snap traps and pitfall traps periodically from 2009 to 2018 at 2 sites in Cowles, New Mexico. Whole gastrointestinal tracts from shrews were screened and tapeworm taxa were identified to genus using high-throughput amplicon sequencing of the 28S rRNA gene. Elements of metacommunity structure (EMS) revealed coherent, dynamic cestode metacommunities indicative of idiosyncratic responses of parasite taxa to seasonal trends in climate variables. We used boosted regression trees to identify latent variables predictive of cestode metacommunity structure and identified "day of the year" as having the greatest relative influence on parasite community structure, followed by precipitation and host body size. This work demonstrates for the first time the utility of the EMS framework for detecting fine-scale seasonal dynamics in parasitic helminth communities.