Microbial Diversity in the Midgut of the Eri Silkworm (Samia ricini): Ecological Significance and Implications for Sericulture

ABSTRACT: The study examined the midgut microbial composition of Eri silkworms, or Samia ricini, in order to clarify the richness and variety of their bacterial community throughout several gut compartments and developmental phases. A wide variety of microbial taxa that are essential for immunity, nutritional absorption, and digestion were found by us using both culture-dependent and culture-independent approaches. With 22% of the microbial population, Enterococcus took the lead, followed by Acinetobacter (10%), Escherichia-Shigella (9%), and Proteiniphilum (9%). The intricacy of the microbiota was further demonstrated by uncultured bacterial species (9%) and chloroplast-associated bacteria (12%). The midgut was shown to have the largest bacterial load and diversity, making it the main microbial hotspot. A rich and intricate bacterial ecosystem was confirmed by analysing the microbial diversity using Shannon–Wiener and Simpson diversity indices by 16S rRNA gene sequencing. The ecological importance of these microbial communities, their function in host metabolism, and the possibility of using probiotics to improve silk output in sericulture were also investigated in this work. The results shed more light on the gut microbiome of lepidopterans and its wider effects on nutrition, insect health, and sustainable sericulture methods.