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The hibernation of amphibians can offer a unique window into overwintering adaptation processes and host–gut microbiota interactions through changes in metabolic availability and homeostasis. We attempted to identify differences in the physiology and gut microbiome during and after hibernation in Japanese wrinkled frogs (Glandirana rugosa), an aquatic overwintering amphibian. After hibernation, the high alpha and beta diversity of the gut bacterial community appears to reflect the more diverse and complex environmental conditions. During winter, Proteobacteria dominated the majority of the gut bacterial community, likely due to high oxygen saturation. After hibernation, Firmicutes and Bacteroidetes increased, which are supportive of host metabolism by gut microbiota. Corticosterone also showed high values and variances after hibernation, presumably allowing the population to remain adaptable across a broad range of environmental gradients. Innate immunity was high after hibernation but exhibited low variation among populations, which supports the idea of a prioritized investment in immunity after hibernation. Blood biochemistry suggests that aquatic overwintering frogs have a mechanism to adapt through overhydration and regulate homeostasis through water excretion associated with the kidney and urine after hibernation. Frog populations exhibit variations and adaptability in gut microbiota and physiology during and after hibernation: Through this, they may demonstrate an adaptive response that regulates metabolic availability in preparation for unpredictable environmental changes. We also propose that the maintenance of Proteobacteria during hibernation can support the colonization of Firmicutes and Bacteroidetes after hibernation, underscoring the need to study the complex effects of gut microbiota across multiple life stages. [ABSTRACT FROM AUTHOR]

BACKGROUND: Invasive species such as the yellow‐legged hornet (Vespa velutina), along with four other Vespa species – Vespa analis, Vespa crabro, Vespa ducalis, and Vespa mandarinia – pose significant threats to the environment, economy, and human health. This study focuses on understanding the key factors contributing to the successful invasion of these species, particularly V. velutina, in South Korea. The analysis encompasses the gut bacterial communities and stable isotopes of carbon and nitrogen of the queen hornets, aiming to identify variances in gut microbial composition and food resource utilization. RESULTS: The gut bacterial communities in the five Vespa species were primarily composed of Proteobacteria, with Firmicutes and Bacteroidetes present. Vespa velutina and V. mandarinia had higher Firmicutes abundance at the phylum level, possibly indicating an increased capacity for dietary fiber breakdown and short‐chain fatty acid production, providing them with a competitive edge. No significant differences in nitrogen and carbon stable isotope values were found among the five Vespa species, suggesting that they fed on similar food sources. However, V. velutina had a higher number of unique gut bacterial operational taxonomic units (OTUs), implying adaptation through the acquisition of a distinct gut bacterial set. Significant correlations were found between the observed index and the Shannon index, and between δ15N and the observed index, suggesting that the food source diversity may influence the gut bacterial community diversity. CONCLUSION: Our study offered valuable insights regarding the adaptation of V. velutina to its new environment in South Korea. The potential role of gut microbiota in the success of invasive species was elucidated. This information is crucial for the management of invasive species, targeted control methods, and implementing preventive regulations. Further studies with larger sample sizes and comprehensive sampling are required to gain a complete understanding of the gut microbiota of Vespa species and their adaptation to new environments. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

This study examines the gut bacterial communities of four necrophagous fly species: Lucilia illustris, L. caesar, Chrysomya megacephala, and C. pinguis. The gut bacterial communities exhibited significant variation across species, showcasing a diverse range of bacterial phyla, classes, and genera. Each species harbored a unique set of bacteria, yet there was considerable overlap in taxa among species. Species richness was comparable across all species. However, measures that account for both richness and evenness, such as the Shannon diversity index and the inverse Simpson's diversity index, indicated significant differences between species, especially between L. illustris and C. pinguis. The functional profiles of the gut bacterial communities mainly centered on metabolic and environmental information processing functions, with no marked differences between species. While this study had limitations in data collection, it still revealed a significant correlation between the phylogenetic distances of some fly species and the distances of their gut bacterial communities. This supports the hypothesis that the gut microbiota is not random but is influenced by the host's evolutionary history or seasons. We confirmed that an association between phylogeny and gut bacterial community structure, as determined through entanglement analysis, exists. The study focused on only five individuals from the four fly species sampled during spring and summer, which might affect the generalizability of the results. Future research would benefit from replicating this study with a larger sample size across various seasons to ensure the more widespread applicability of the findings. [ABSTRACT FROM AUTHOR]