Researchers at the University of East Anglia have found that Seychelles warblers with closer social ties share more similar gut microbes, particularly anaerobic types spread through direct contact. The study on Cousin Island suggests social interactions drive this microbial exchange. Similar effects likely occur among humans living together.
A team led by Dr. Chuen Zhang Lee from UEA's School of Biological Sciences analyzed fecal samples from Seychelles warblers on Cousin Island. Over several years, they collected hundreds of samples from birds in known social groups, including breeding pairs and helpers. This allowed comparisons between birds interacting closely at nests and those in different groups. The focus was on anaerobic gut bacteria, which require low-oxygen conditions to survive and spread only via direct contact, not environmental drift. Dr. Lee stated: 'The more social you are with another individual, the more you share similar anaerobic gut bacteria.' Birds spending time together, such as couples and helpers, exhibited highly similar microbiomes for these microbes. Prof. David S. Richardson highlighted Cousin Island's advantages: 'It is small, isolated, and the warblers never leave it,' enabling lifelong tracking of individually marked birds with colored leg rings. This setup mimics lab conditions while preserving natural behaviors and diets. The findings indicate social bonds, beyond shared spaces, transmit beneficial gut bacteria important for digestion and immunity. Dr. Lee noted potential human parallels: 'Whether you're living with a partner, housemate, or family, your daily interactions may encourage the exchange of gut microbes.' Sharing these bacteria through hugs, shared food prep, or close proximity could enhance household health. The research, involving collaborators from Norwich Research Park and others, appears in Molecular Ecology.
