Abstract
Animal bodies harbour a complex and diverse community of microorganisms and accumulating evidence has revealed that microbes can influence the hosts’ behaviour, for example by altering body odours. Microbial communities produce odorant molecules as metabolic by-products and thereby modulate the biochemical signalling profiles of their animal hosts. As the diversity and the relative abundance of microbial species are influenced by several factors including host-specific factors, environmental factors and social interactions, there are substantial individual variations in the composition of microbial communities. In turn, the variations in microbial communities would consequently affect social and communicative behaviour by influencing recognition cues of the hosts. Therefore, microbiota studies have a great potential to expand our understanding of recognition of conspecifics, group members and kin. In this review, we aim to summarize existing knowledge of the factors influencing the microbial communities and the effect of microbiota on olfactory cue production and social and communicative behaviour. We concentrate on avian taxa, yet we also include recent research performed on non-avian species when necessary.
Highlights
Are body odours just the by-products of our physiology and poor personal hygiene or are they valuable signals produced by bacteria, providing cues to other individuals about ourselves?The sweaty scent of human armpits is not the smell of the sudoriferous secretion, but the result of commensals on our skin, digesting its compounds into volatile, odorous molecules [1]
We focus on avian taxa, yet the vast majority of microbiome studies have been conducted in non-avian species such as mammals and insects, leaving bird microbiota relatively under-investigated
Feather-degrading bacteria could be involved in odour production via breaking down feather components into small, possibly volatile, fragments. Because of their extended surface, feathers offer a great surface for odours to emerge from a bird, to the best of our knowledge, far no study has investigated this possibility
Summary
Are body odours just the by-products of our physiology and poor personal hygiene or are they valuable signals produced by bacteria, providing cues to other individuals about ourselves?. Genes 2018, 9, 387 signals produced by microorganisms might influence the hosts’ behaviour [15,16,17] This idea was postulated in the late 70s as the “fermentation hypothesis of chemical recognition”, which states that microbially-derived olfactory molecules mediate social communication in mammals [11,18]. As the composition of the symbiotic microbiota is influenced by several factors (including the phylogeny of the host, life-history traits such as age and sex, the genetic structure of the host, social interactions, and environmental variables such as diet and habitat), microbe-specific odorants might transfer this information about the host This information might be very difficult to fake and is likely to be an honest signal in intraspecific communication. We will end our review discussing potential evolutionary implications of microbe induced odours and the advantage of studying birds
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
