Authors
A Sweeny1; 1 University of Shefield, UK Discussion
Host-associated microbial communities (the microbiome) are intimately tied to host fitness, with important implications for wildlife disease dynamics. Despite growing interest, the relationship between microbiome community composition, host phenotypes, and subsequent consequences for population dynamics is difficult to determine due to the high resolution of longitudinal sampling and host metadata required. Furthermore, relationships between commensal and parasitic within-host communities are very poorly resolved due to the high complexity of the data. The Soay sheep of St Kilda are an unmanaged ungulate population monitored as part of an iconic long-term study system with an unparalleled wealth of host phenotype information. In this population, we monitored the gut microbiome & parasite communities of ~1600 samples from 400 unique individuals for 2 years using metabarcoding approaches on non-invasive faecal samples. Using modern mixed modelling approaches, we find that both gut microbiome and parasite communities vary substantially across seasons and especially between age classes. I will present causes and consequences of this and other variation in this longitudinal study and describe how dynamics of the microbiome align with those of the parasite community. Finally, I will discuss the implications of findings from this and other systems for understanding how animal microbiomes may respond to changing environments, and how these effects might influence population and disease dynamics in the wild. 
