Insect-pathogen interactions can be influenced by many factors including host life history, behavior and abiotic factors, such as chemical exposure. Additionally, exposure to pathogens can have transgenerational implications and influence the susceptibility of offspring. Understanding the outcomes of these interactions can also have implications for developing effective control strategies for insect pests. Asian longhorned beetles, Anoplophora glabripennis, are invasive wood borers which have been introduced into North America and Europe and the entomopathogenic fungus Metarhizium brunneum is being developed for their control. Studies were conducted to determine how sexual maturity, insect age, mating status (unmated vs mated), host thermoregulatory behavior, and prior maternal pathogen exposure influence A. glabripennis susceptibility to M. brunneum and ability to suppress a fungal infection, even across a generation. Additionally, potential mechanisms of synergy between M. brunneum and the neonicotinoid pesticide imidacloprid were investigated. Beetles did not exhibit thermoregulatory behavior although it would have been beneficial. Prior maternal pathogen exposure enhanced offspring survival but whether offspring survival was enhanced depended on the pathogen used to expose mothers and whether or not the pathogen was living or dead. Beetle susceptibility to A. glabripennis was iii also influenced by the age and mating status of beetles. We found that old beetles were not more susceptible than younger beetles and only found a cost of mating for mature but not old beetles. Finally we found that starvation may be a potential mechanism for the synergy between a pesticide (imidacloprid) and the fungal pathogen M. brunneum. These findings provide insight into insect-pathogen interactions and ecoimmunology in beetles. iv