Microbiome and climate: skin microbial diversity and community functions of <i>Polypedates megacephalus</i> (Anura: Rhacophoridae) associated with bioclimate

The microbiome inhabiting animal skin plays a crucial role in host fitness by influencing both the composition and function of microbial communities. Environmental factors, including climate, significantly impact microbial diversity and the functional attributes of these communities. However, it remains unclear how specific climatic factors affect amphibian skin microbial composition, community function, and the relationship between these two aspects. Understanding these effects is particularly important because amphibians are poikilotherms and, thus, more susceptible to temperature fluctuations. Here, we investigated the skin microbiome of the rhacophorid tree frog <i>Polypedates megacephalus</i> across different climatic regimes using 16S rRNA gene sequencing. Skin swab samples were collected from nine populations of <i>P. megacephalus</i> adults in the Guangxi region, China. The majority of the core microbiota were found to belong to the genus <i>Pseudomonas</i>. Our findings indicate that microbial community diversity, composition, and function are associated with changes in climatic conditions. Specifically, the taxonomic and functional diversity of the skin microbiome increased in response to higher climate variability, particularly in temperature fluctuations. Additionally, the functional traits of microbial communities changed in parallel with shifts in community diversity and composition. The significant correlations of the functional redundancy index with climatic factors suggest that environmental filtering driven by climate change impacts microbial community functional stability. These results highlight the critical influence of climatic factors on amphibian skin microbiomes and offer new insights into how microbial composition and function contribute to host adaptation in varying environmental conditions.IMPORTANCEThis study is important in understanding the association between climate variability, microbial diversity, and host adaptation in amphibians, which are particularly vulnerable to environmental changes due to their poikilothermic nature. Amphibians rely on their skin microbiome for key functions like disease resistance, yet little is known about how climate fluctuations impact these microbial communities. By analyzing the microbiome of <i>Polypedates megacephalus</i> across different climatic regimes, our analysis reveals that warmer climates could reduce the microbial diversity and community functional redundancy, indicating the functional stability of skin microbiome could be susceptible to climate variability, particularly in hosts adapted to relatively cooler conditions. These findings highlight the potential ecological consequences of climate change and emphasize the need to integrate microbiome health into amphibian conservation strategies.