Petrullo Lauren, Webber Quinn, Raulo Aura, Boutin Stan, Lane Jeffrey E, McAdam Andrew G, Dantzer Ben
Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, Arizona, USA.
Department of Psychology, University of Michigan, Ann Arbor, Michigan, USA.
Ecol Lett. 2025 Aug;28(8):e70186. doi: 10.1111/ele.70186.
Microbial transmission is hypothesised to be a major benefit of sociality, facilitated by affiliative behaviours such as grooming and communal nesting in group-living animals. Whether microbial transmission is also present in animals that do not form groups because territoriality limits interactions and prevents group formation remains unknown. Here, we investigate relationships among gut microbiota, population density and dynamic behavioural and spatial measures of territoriality in wild North American red squirrels (Tamiasciurus hudsonicus). Periods of high population density predicted population-level gut microbial homogeneity but individual-level diversification, alongside changes in obligately anaerobic, non-sporulating taxa indicative of social transmission. Microbial alpha-diversity increased with more frequent territorial intrusions, and pairs with stronger intrusion-based social associations had more similar gut microbiota. As some of the first evidence for social microbial transmission in a solitary system, our findings suggest that fluctuations in density and territorial behaviours can homogenise and diversify host microbiomes among otherwise non-interacting animals.
微生物传播被认为是群居生活的一个主要益处，在群居动物中，诸如梳理毛发和共同筑巢等亲和行为促进了微生物传播。对于那些因领地行为限制了互动并阻碍群体形成而不形成群体的动物，微生物传播是否也存在仍不明确。在此，我们研究了野生北美红松鼠（Tamiasciurus hudsonicus）的肠道微生物群、种群密度以及领地行为和空间测量动态之间的关系。高种群密度时期预示着种群水平的肠道微生物同质性，但个体水平的多样性，以及表明社会传播的专性厌氧、非芽孢类群的变化。微生物α多样性随着领地入侵频率的增加而增加，基于入侵的社会联系更强的配对个体拥有更相似的肠道微生物群。作为独居系统中社会微生物传播的一些初步证据，我们的研究结果表明，密度和领地行为的波动可以使原本不相互作用的动物之间的宿主微生物群同质化和多样化。
