Influence of Seasonal Variations on Gut Microbiota of Gekko japonicus

In ectothermic vertebrates, seasonal dietary shifts and temperature fluctuations are major ecological drivers of gut microbiota remodeling, with important implications for host adaptation. The widely distributed nocturnal reptile Gekko japonicus provides an effective model for exploring seasonal gut microbiota dynamics under natural conditions. In this study, wild gecko individuals were sampled in spring, summer, and autumn, and gut microbial composition and potential functions were characterized using 16S rRNA gene amplicon sequencing and bioinformatic analyses. Our results demonstrated that microbial diversity and richness were lowest in spring, whereas richness increased significantly in summer. Community dissimilarity showed a significant positive correlation with the temporal interval between sampling seasons, with clear separation between spring and autumn microbiota. Bacteroidetes were significantly enriched in spring, potentially reflecting the legacy effects of winter hibernation and prolonged fasting. Conversely, autumn was marked by increased abundance of the Firmicutes and Proteobacteria, suggesting a potential enhancement of the host's capacity for energy harvest from the diet. Collectively, these results demonstrate that seasonal environmental variation strongly shapes gut microbiota richness and composition in G. japonicus. Such dynamic microbial restructuring likely represents an adaptive ecological strategy that facilitates host adjustment to seasonal environmental heterogeneity and optimizes energy assimilation.