INSECT GUT MICROBIOTA: DIVERSITY, FUNCTIONAL ROLES, AND EMERGING ECOLOGICAL AND APPLIED PERSPECTIVES—A REVIEW

Abstract

Insects are the species-rich and ecologically significant animals inhabiting our planet. They perform vital ecosystem services such as pollination, nutrient recycling, and are involved in food webs and agriculture. Gut microbiota, complex microbial communities residing within the digestive tracts of insects, play an important role in shaping the success of insects in their environment. This review discusses insect gut microbiota in terms of its diversity and functional attributes that can contribute to ecological and applied relevance. The insect gut is taxonomically diverse and includes bacteria, archaea, fungi, and protists. Furthermore, the anatomical division of the insect stomach into the foregut, midgut, and hindgut provides distinct environmental variables, including pH, redox potential, and digestive enzymes, which determine the organization of the gut microbial population. Recent developments in next-generation sequencing approaches like 16S rRNA amplicon sequencing, shotgun metagenomics, and metatranscriptomics have allowed researchers to study gut microbial diversity and functions with great depths. Gut microbes can confer several benefits to their host including nutrition, detoxification of host-plant toxins and pesticides, immune defense, and regulation of host development and reproduction. Ecologically, insects and their gut microbes shape host-plant relationships, insect behavior and social interactions, tolerance to abiotic stresses, and insect-microbe-plant networks involved in ecosystem functioning. Practically, gut microbiota can be exploited for biological pest control using Wolbachia-based bio pesticides and microbial symbionts. Gut microbes of pollinators can be targeted for probiotics and prebiotics to increase pollinator fitness. Microbial enzymes could be utilized for various industrial applications. Finally, this review highlights major knowledge gaps in gut microbiota including modes of inheritance, functional redundancy, and responses to environmental disturbances. Future research that combines various omics approaches with ecological experiments will be crucial for unlocking the full potential of insect gut microbiota in agriculture, conservation, and biotechnology.