| dc.description.abstract | The microbiome is important for many functions in animals, for example digestion, skin health and communication. Microbiome and immune system interactions are especially interesting in relation to possible odour signalling. For birds, the feather microbiome is still mostly unknown and studies on the microbiome and immune system interactions are few. In this thesis I have investigated feathers from two different body areas of social pairs of bluethroats (Luscinia svecica), feathers surrounding the preen gland and feathers surrounding the cloaca. Microbial composition was analysed by sequencing the V3-V4 region of the 16S rRNA fragment. Firstly, I investigated if there were differences in microbial diversity for different sexes, ages, and feather areas. Secondly, I investigated if observed dissimilarity of microbial diversity in pairs would differ from random expectations. Lastly, I investigated associations between microbiome diversity and MHC allele diversity. I did not find any significant differences in microbial diversity between sexes, age-classes, or feather areas. No evidence was found that microbial dissimilarity in pairs differed from expected values based on random mating. However, I did find a positive correlation between the microbiome dissimilarity in pairs and MHC in preen feathers. There is a good possibility that the feather microbiome in the bluethroat plays a role between the sexes and MHC-based mate-choice. | eng |