Abstract:Insects are the most diverse and abundant group of organisms dominating terrestrial habitats, in terms of numbers of species. The evolutionary success of insects and their diversification into a wide range of ecological niches depends in part on the beneficial members of their associated microbiome. The insect is colonized by a complex population of microorganisms in a symbiotic relationship, which vary from bacteria to viruses, yeasts, and protists. These diverse microbial communities provide important physiological functions for the insect hosts in many ways, including provision of nutritional supplements, enhancement of digestive mechanism, tolerance of environmental perturbations, modulation of host immune homeostasis, protection from parasites and pathogens, modulation of vector competence, contribution to inter-and intra-specific communication, and influence of insect mating and reproduction. Conversely, the insect host can affect the microbial community. Therefore, the insect symbionts can no longer be ignored when studying insect biology and host-pathogen interactions. Insect symbionts have become promising in the development of novel tools for the biological control of insect pests, biodegradation of wastes and blocking the transmission of insect-borne diseases. Here, we provide an overview on diversity of insect symbionts, the latest advance in the understanding of symbiotic relationships, interactions between insect and symbionts, and in developing novel strategies for controlling insect pests and vectorborne diseases. Finally, directions for future work are discussed.