Lead author Dr Katerina Johnson, a research associate in the Department of Experimental Psychology and Psychiatry at the University of Oxford, said: “Here we show that more sociable monkeys have higher concentrations of beneficial gut bacteria, and a lower abundance of potentially disease-causing monkeys.” of the bacteria that do it.”
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monkey Island
The scientists focused on a single social group of rhesus macaques (with 22 males and 16 females between the ages of six and 20) on Cayo Santiago Island, off the east coast of Puerto Rico.
Macaques originally lived only in North Africa and Asia. But in 1938, a founding population of 409 rhesus macaques was transferred from India to Cayo Santiago. Today, more than 1,000 macaques live on the 15.2-hectare island, divided into several social groups.
They range and forage freely, although their diet is supplemented daily with monkey chow. Researchers conduct behavioral observations on monkeys every year.
Between 2012 and 2013, the authors collected a total of 50 uncontaminated stool samples from this social group. As a measure of social connectedness, they used the amount of time each monkey spent grooming or being groomed and the number of grooming partners it had in 2012 and 2013.
social grooming
Co-author Dr Carly Watson from the Institute of Cognitive Science at the University of Colorado Boulder explained: “Macaques are highly social animals and grooming is their main way of forming and maintaining relationships, so grooming provides a good indicator of social bonding.”
Johnson, Watson et al. analyzed DNA sequence data from stool samples to measure composition and diversity of the gut microbial community, and looked at relationships with social interaction.
They also took into account gender, age, season, and rank within the group hierarchy. They focused on microbes that have repeatedly been shown to be more or less abundant in people or rodents with autism-like symptoms (usually accompanied by social disconnection) or who are socially disadvantaged.
Sociable monkeys have more ‘good’ microbes
“Engagement in social interactions was positively related to the abundance of certain gut microbes with beneficial immunological functions, and negatively related to the abundance of potentially pathogenic members of the microbiota,” said co-author Dr. Philip Burnett, co-author Dr. Philip Burnett. was related to abundance.” Psychiatry at the University of Oxford.
For example, the most sociable monkeys contain more abundant Faecalibacterium and Prevotella. In contrast, the genus Streptococcus, which can cause diseases such as strep throat and pneumonia in humans, was most abundant in the less sociable monkeys.
“It is particularly striking that we find a strong positive correlation between the abundance of the gut microbe Faecalibacterium and how sociable the animals are. Faecalibacterium is known for its potent anti-inflammatory properties and is associated with good health, Johnson said.
Cause and effect?
but What is the relationship between social connectedness and gut microbiome composition? Distinguishing between cause and effect is not easy.
“The association between social behavior and microbial abundance may be a direct result of social transmission of microbes, for example through grooming. It may also be an indirect effect, as monkeys with fewer friends may be more stressed, which then Affects the abundance of these microbes.
With all behavior affecting the microbiome, we also know it’s a reciprocal relationship, Thereby the microbiome can influence the brain and behavior,” Johnson said.
Co-author Dr Robin Dunbar, a professor in the Department of Experimental Psychology at the University of Oxford, said: “As our society increasingly substitutes online interactions for real life, these important research findings underline the fact that as primates , we have evolved not only in a social world but also a microbial one.”
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