The “gut–microbiota–brain axis” reveals that gut microbiota plays a critical role in the orchestrating behavior of the host. However, the correlation between the host personalities and the gut microbiota is still rarely known. To investigate whether the gut microbiota of Mongolian gerbils (Meriones unguiculatus) differs between bold and shy personalities, we compared the gut microbiota of bold and shy gerbils, and then we transplanted the gut microbiota of bold and shy gerbils into middle group gerbils (individuals with less bold and shy personalities). We found a significant overall correlation between host boldness and gut microbiota. Even though there were no significant differences in alpha diversity and beta diversity of gut microbiota between bold and shy gerbils, the Firmicutes/Bacteroidetes phyla and Odoribacter and Blautia genus were higher in bold gerbils, and Escherichia_shigella genus was lower. Furthermore, the fecal microbiota transplantation showed that changes in gut microbiota could not evidently cause the increase or decrease in the gerbil’s boldness score, but it increased the part of boldness behaviors by gavaging the “bold fecal microbiota”. Overall, these data demonstrated that gut microbiota were significantly correlated with the personalities of the hosts, and alteration of microbiota could alter host boldness to a certain extent.

Background The "pace-of-life" syndrome (POLS) framework can encompass multiple personality axes that drive important functional behaviors (e.g., foraging behavior) and that co-vary with multiple metabolic and/or life history traits. However, the empirical evidence for the relationships between animal personality and foraging strategies remains unclear, including their fitness consequences in the POLS framework. Therefore, the POLS hypothesis might be limited, and the environmental context could influence this linkage. In this study, the Mongolian gerbil (Meriones unguiculatus), a social rodent, was used as a model system to investigate how boldness or shyness is associated with foraging strategies in the food hoarding season and over-wintering survival or reproduction at individual and group levels. Results Our results showed that bold and shy gerbils had different foraging strategies and over-wintering adaptations. Compared with shy gerbils, bold gerbils had a lower effort foraging strategy, including higher latency, less frequency, and shorter duration when foraging during the food hoarding season, and exhibited lower over-wintering survival, but bold-shy personality differences had no effect on over-wintering reproduction. Conclusion These findings suggest that animal personality is a key factor that affects the foraging strategy during the food hoarding season in Mongolian gerbils. Personality may be related to energy states or the reaction to environmental change (e.g., predation risk, food availability) in bold or shy social animals. These results reflect animal life history trade-offs between "current versus future reproduction" and "reproduction versus self-maintenance", thereby helping Mongolian gerbils adapt to seasonal fluctuations in their living environment.