Diversity and functions of the gut microbiota in Lepidoptera insects

Insects, the most diverse group of organisms on earth, harbor a rich array of gut microbes. These gut microbiota exert direct and indirect influences on their hosts, playing pivotal roles in critical physiological processes including growth and development, reproduction, nutrient metabolism, immune defense, plant-insect interactions, and detoxification of harmful substances. Lepidoptera, the second-largest order within the class Insecta, exhibit remarkable diversity in their gut microbiota both within and across species. Integration of molecular biology techniques into gut microbiota research has stimulated growing interest worldwide in exploring the gut microbiota of lepidopterans. This review provides a comprehensive assessment of the known diversity, transmission pathways, driving factors, and biological effects of lepidopteran gut microbes, and describes mechanisms underlying the interactions between lepidopteran insects and their gut microbiota, establishing a theoretical foundation for pest management strategies and the development and utilization of lepidopteran gut microbiota, thereby contributing to sustainable agricultural and economic development.