Abstract: Insect symbionts are microorganisms that establish enduring and sustained associations with insect hosts. These microorganisms inhabit the body surface, gut, hemocoel, or intracellular cells of insects, participating in the regulation of various physiological functions of their host insects. Research on insect-symbiont interactions involves multidisciplinary collaboration. In-depth exploration of the functions of insect symbionts and their interactions with hosts not only advances our understanding of fundamental mechanisms in the life sciences but also introduces innovative perspectives and methods for pest management, vector-borne disease control, and optimal utilization of beneficial insects. In recent years, Chinese researchers have made noteworthy progress in the insect microbiome and got significant achievements in many research directions. In this article, we provided an overview of the most recent research progress in insect symbionts, introduced the main contents of this special issue, and proposed three noteworthy research directions: (1) the functions of insect intracellular symbionts; (2) the mechanisms by which insects regulate the abundance and transmission of symbionts; and (3) genetic modification and application of insect symbionts.

Key words:  Insect symbionts, intracellular symbionts, obligate symbionts, facultative symbionts, gut microbes, genetic modification