University of Oxford researchers have demonstrated that the social connections of wild mice have a strong influence on the microorganisms found in their guts. The research also found that social contact is influential and spreads a different set of gut microbes than those transferred through a shared environment.
In other words, social interactions (such as grooming) between animals provide key pathways for gut bacteria, many of which cannot survive in the outside environment, to spread.
This was shown from an assessment of 100 wild wood mice (Apodemus sylvaticus) living in Wytham Woods, Oxfordshire. The tracking process enabled an assessment of the mice and their social associations with each other to be made over a period of 10 months.
The microbial data came from sequencing data relating to the DNA of gut bacteria recovered from the mice faeces.
By linking their microbiome to their behavioural patterns, the scientists found that gut microbes could spread both through social networks and shared environments, but these social and environmental routes of spread had very different effects.
Overall, social networks had a much stronger influence on the gut microbiome, with pairs of socially associated mice sharing many more bacteria than mice that were only using the same environment.
The analyses also suggested that social and environmental contacts spread different types of gut microbes, with anaerobic (oxygen-intolerant) bacteria more dependent on social contacts, while oxygen-tolerant bacteria could be shared through the environment.
Lead author Dr Aura Raulo says in a statement provided to Digital Journal: “We were surprised to find that different gut microbes spread through social contacts and shared environments among mice. This implies that social behaviour and contacts with the natural environment may affect different parts of our microbiome, which could have different effects on our health.”
As an example, anaerobic bacteria, being ‘stuck’ inside their hosts, are thought to harbour more potential to be mutualistic (friendly) and healthy for their hosts. Oxygen-tolerating microbes, which can thrive either inside or outside an animal host and whose fate is less dependent on the host’s wellbeing, are thought to be more likely to cause disease.
The results also suggest that social behaviours can play an important role in health, even in less social species. For example, of possible exploration with people, reduced environmental contact of urban lifestyles may have negative impacts on our microbiomes and may be associated with issues such as allergies and immune diseases.
The research appears in the journal Nature Ecology & Evolution. It is titled “Social and environmental transmission spread different sets of gut microbes in wild mice.”
