Ecological and functional dynamics of gut microbiota in the model insect, silkworm Bombyx mori

The silkworm (Bombyx mori) has emerged as a powerful invertebrate model for gut microbiome research due to its simple yet representative gut microbiota, cost-effective rearing, and established germ-free systems. This review synthesizes current knowledge on the ecological drivers and functional roles of silkworm gut microbiota, emphasizing its interaction with host health, environmental adaptation, and biotechnological applications. The microbial community of silkworms is highly plastic, shaped by various intrinsic (developmental stage, sex) and extrinsic (diet, environmental conditions) factors. Key microbial taxa, including Enterococcus, Bacillus, Acinetobacter, Pseudomonas, and Staphylococcus, form a dynamic core community with demonstrated probiotic attributes. These microbes contribute to nutrient metabolism (such as cellulose digestion and amino acid synthesis), immune modulation (through the production of antimicrobial peptides), and detoxification (by degrading xenobiotics). Meanwhile, their dysbiosis correlates with reduced growth, silk yield, and pathogen resistance. Notably, several gut symbionts produce or stimulate natural antimicrobial proteins, including bacteriocins (such as enterococcin LX) and host-derived antimicrobial peptides, which exhibit activity against microbial pathogens. Understanding these microbial associations is crucial for developing microbe-based probiotic formulations, antimicrobial therapies, and enzyme-driven bioprocesses to enhance sericultural productivity and sustainability. Despite progress, significant gaps remain in our understanding of host-microbe coevolution, immune-microbiota crosstalk, and the genetic basis of microbial resilience. Future research integrating multi-omics approaches and gnotobiotic models will unravel mechanistic insights, enabling targeted manipulation of the silkworm microbiota for agricultural, environmental, and medical innovations.