There are a wide variety of microorganisms in insects, which form a close symbiotic relationship with its host insect in the long-term co-evolutionary process. In recent years, with the rapid development of molecular biology techniques, the diversity of microbes in insects has been gradually explored.The diversity of microbial communities in insects is not only closely related to the sex, developmental phases, and species, but also to food, temperature, CO₂ concentration, and irradiation. Limitations of research methods can also be a factor.