Geographical diet variations and microbial diversity: insights into François' langur's adaptive strategies

The diversity in foraging behavior observed among species is indicative of their ability to adapt to specific environmental conditions, with dietary differences playing a crucial role in shaping the composition of gut microbiota. However, there are limited reports on the dietary habits and gut microbiota of François' langur (Trachypithecus francoisi) across different wild geographical populations. To address this, our study employed DNA metabarcoding and 16S rRNA sequencing to investigate variations in dietary composition and their influence on gut microbiota among distinct wild populations of François' langur, as well as among different groups within the same region. The dietary analysis revealed a broad diet, identifying 134 families and 336 genera of plants. The habitat quadrat survey results indicate significant differences in the habitats of François' langurs across different geographic populations. However, the dietary composition analysis reveals that while the food composition of different groups within the same region is relatively similar, there are notable differences across geographically distinct regions. The microbial community analysis demonstrated distinct compositional and structural divergence in gut microbiota between these populations, whereas no significant microbial differences were detected among groups within the same region. Further correlation analysis between diet and microbiota indicated that dominant plant taxa in the diet exhibited significant associations with Firmicutes, Proteobacteria, and other microbial phyla, displaying varying degrees of positive or negative correlations. This study elucidates how dietary variations among geographically distinct populations of François' langur drive changes in gut microbiota, reflecting their adaptive responses to local habitats. These findings provide valuable insights for the conservation management of François' langur populations and potential applications in health status monitoring.IMPORTANCEUnderstanding the mechanisms by which animals adapt to their environment is essential for effective conservation efforts. This study examines the endangered François' langur, focusing on the largely unexplored relationship between its dietary habits and gut microbiota across various wild populations. Our research indicates that although habitat vegetation varies significantly even among groups within the same region, their diets remain similar. Conversely, langur populations from distinct geographic areas exhibit notable dietary differences. These dietary variations, in turn, lead to distinct compositional differences in their gut bacterial communities. This diet-microbiome interaction serves as a crucial physiological indicator of how these primates adapt to their local forest environments. By illustrating that gut microbiota composition reflects an animal's ecological response to its environment, this study offers a powerful and non-invasive tool for conservation. These findings are critical for developing targeted strategies, such as habitat restoration, and for monitoring the health of these rare primates through gut microbiome analysis.