Abstract: Insects, the largest group of multicellular organisms on the Earth, are notable for their numerous species and varied morphology, generally harboring abundant microbes in their digestive tract. These microorganisms help the host in digestion, nutrition absorption, pheromone synthesis, as well as playing a role in the defense of harmful invaders, which strengthen the host immune activity. Lepidoptera is the second largest order in Insecta, with many common pest and beneficial insect species. Many methods and techniques have been developed for the research on the gut microbiota, which becomes a hot research topic in recent years. This review outlines the research of gut microbiota in lepidopteran insects (e.g., Bombyx mori, Spodoptera littoralis and Plutella xylostella), including gut environment, microbial diversity and research methods. Furthermore, the community structure of several lepidopteran model insects and the roles of gut microbes in host’s detoxification and immune system are summarized. The findings we review here should be valuable for the further research on the gut microbiota in lepidopteran insects, and pave the way for developing novel strategies to control pests and protect beneficial insects.

Key words: Lepidopteran insect, gut, gut microbiota, gut environment, diversity, coevolution