Coding of group odor in the subcaudal gland secreation of the European badger Meles meles: chemical composition and pouch microbiota

The fermentation hypothesis predicts that odor profiles of mammals depend partly on the primary gland products excreted by the animal and partly on the composition of the bacterial flora converting these into secondary metabolites. Some mammalian odors, such as shared group odors, however, need to be consistent yet flexible (e.g., to allow for changes in social-group affiliation), and are thus predisposed for microbial mediation. Using terminal restriction fragment (TRF) length polymorphism analyses we analyzed the microbial community in subcaudal-gland secretions of European badgers (Meles meles) in relation to the chemical scent profiles as determined by gas chromatography-mass spectrometry analyses (GCMS) of 66 adults belonging to six different social groups. We found a total of 50 TRFs and 125 different chemical compounds with a subset of four TRFs best explaining the structure in the chemical matrix. Nevertheless, although semiochemical profiles were group specific, microbial profiles were not. In our approach, however, the number of operational taxonomic units exceeded the numbers of TRFs, and thus our analyses were likely limited by the afforded resolution. As it is likely that the variation in metabolic activity is found at the species-, subspecies-, or even strain-level, future high-throughput sequencing can be expected to reveal more subtle differences in the microbial communities between social groups.