Microbial transmission in animal social networks and the social microbiome

Abstract

Host-associated microbiomes play an increasingly appreciated role in animal metabolism, immunity, and health. The microbes in turn depend on their host for resources and can be transmitted across the host's social network. In this article, we describe how animal social interactions and networks may provide channels for microbial transmission. We propose the 'social microbiome' as the microbial metacommunity of an animal social group. We then consider the various social and environmental forces that are likely to influence the social microbiome at multiple scales, including at the individual level, within social group, between groups, within populations and species, and finally between species. Through our comprehensive discussion of the ways in which sociobiological and ecological factors may affect microbial transmission, we outline new research directions for the field.

The importance of individual-to-society feedbacks in animal ecology and evolution

“…Together, these studies demonstrate that the pattern of the social structure and the nature of the pathogen or parasite interact to determine the transmission pathways and dynamics of disease spread. More recently, a similar feedback has been proposed regarding the dispersal of mutualistic and commensal microorganisms through social contact-while the microbial transmission can be modulated by the hosts' social environment, the hosts' physiology can in turn modulate the microbiota of that social environment (see Sarkar et al 2020).…”

Age Patterning in Wild Chimpanzee Gut Microbiota Diversity Reveals Differences from Humans in Early Life

“…Surprisingly, given evidence of human mother to infant vertical transmission of microbes 13,14 and expected dilutions of this signature over time, 15 the gut microbial communities of young infants were not more similar to the microbiotas of their mothers than were the gut microbial communities of offspring in older age classes ( Figure S2A). In fact, young infants were significantly more dissimilar from their mothers than were offspring in other age groups (p = 0.016; likelihood tests of linear mixed effects models), a result that reinforces the distinctiveness of the infant chimpanzee gut microbiota.…”

Host adaptation in gut Firmicutes is associated with sporulation loss and altered colonisation patterns

“…Once ingested, gut bacteria must transit through the gastrointestinal tract, contend with the human immune system and compete with indigenous bacteria for nutrients and replicative niches to colonize 5,7 . Transmission of the intestinal microbiota is an ongoing lifelong process starting with maternal transmission around birth and continuing throughout life, especially between co-habiting individuals in regular contact 8-18 . In fact, gut symbiont transmission during co-habitation has a stronger effect on the composition of an individual’s gut microbiota than human genetics 12 , highlighting the importance of transmission in shaping an individual’s microbiota composition and functions.…”