ANALYSIS OF GEOGRAPHIC VARIABILITY OF FECAL MICROBIOMES OF FRATERCULA ARCTICA AND CROSS-COMPARISON OF FECAL MICROBIOMES OF DIFFERENT AVIAN FEEDING TYPES

Gastrointestinal (gut) microbiota have a multitude of effects on their host, from aiding in digestion, to facilitating nutrient uptake, detoxification, and interactions with the immune system. Multiple factors have been identified that influence the composition of vertebrate microbiomes; these include host genetics, environmental conditions, diet and age, sex, and geography. However, broad inferences about wild avian gut microbial diversity and function under natural conditions are limited. Most knowledge on avian microbiomes is derived from studies on domestic poultry. Information on non-model taxa may provide important contextual information about vertebrate host-microbiome interactions and aid in future management of vulnerable species. Here, the Atlantic puffin’s (Fratercula arctica) fecal microbiome was characterized in an effort to expand current knowledge on gut microbial diversity and function in wild birds. Additionally, Atlantic puffin fecal samples were used to assess how geographic locality affects the abundance of taxa present in the gut microbiomes of wild avian species. The second aim of this study was to assess distinctions in microbiome diversity as a function of feeding type using Atlantic puffins, Anna’s hummingbird (Calypte anna), the small tree finch (Camarhynchus parvulus), the vampire ground finch (Geospiza septentrionalis), gentoo penguins (Pygoscelis papua), and chinstrap penguins (Pygoscelis antarcticus). At the phylum level, Atlantic puffin fecal microbiota was dominated by Firmicutes, Proteobacteria, Fusobacteria, Actinomycetota, and Bacteroidetes. Additionally, puffin microbial communities not only differed among locations but within locations as well, suggesting that each individual has its own unique microbial community that is affected by a multitude of extrinsic and intrinsic factors. Results from the avian metaanalysis revealed statistically significant associations between dietary specializations and fecal microbiota. However, host taxonomy and phylogeny may also play a significant role and preclude diet specializations in determining fecal microbial composition. The three hypercarnivorous piscivores were expected to possess similar fecal microbiota, but the two penguin species were observed to cluster together and distinctively from puffin samples suggesting host taxonomy plays a larger role than dietary specialization