Our symposium examines microscopic organisms or microbes associated with insects and the environment. The collection of microbes in an insect host or environment is called the microbiota. Within the microbiota, individual microbes can play important roles in host health, function, or reproduction. In addition, microbes can interact with each other causing synergistic effects. While our understanding of the microbial players in insects has increased, there are many opportunities to better understand the role of interacting microbes and the communities they form in insect hosts, plants, and soil environments. While the focus of our symposium is in Plant-Insect Ecosystems, the content would provide the ESA community greater insight into the roles microbes can have in their hosts and in the environment.