Understanding fitness consequences of microbiome variation in a wild ungulate population

Individuals are host to trillions of microorganisms (the microbiome), and these communities have pervasive effects on host biology (e.g. immune development, digestion, pathogen defense). These relationships have been harder to discern in wildlife, but likely play a key role in shaping host ecology and evolution. Understanding how fluctuations in the GM might influence their hosts’ fitness will require longitudinal and individual-based data detailing the GM, environmental conditions, and host outcomes. This project will use will use a long-term field study of Soay sheep on the St Kilda archipelago to address key questions about the causes and consequences of variation in the GM in the wild.

Gut microbiome data was collected across four years for individuals in this population alongside fitness, infection, and immunity data. Despite evidence for dynamic changes of wildlife GM during periods of development or in response to seasonal dietary shifts, there is extremely limited evidence that such dynamics alter fitness outcomes. This project will test how community structure and dynamics of the GM influence host health in wild Soay sheep. The student will apply community ecology and microbiome modelling approaches (Sweeny et al. 2023) and integrate analyses with a rich dataset collected alongside GM data detailing parasitological and immunological dynamics (Sweeny et al. 2022; Corripio-Miyar et al. 2022). They will have the opportunity to be involved in field trips for additional data collection on St Kilda and to drive areas of interest to shape our understanding of the role of the microbiome in this long-term system.