Many animals from partnerships with bacteria to protect them from pathogens, nutritional stresses, and other environmental onslaughts. The eusocial honey bee, Apis mellifera, is host to a characteristic, and specific microbial community and one member of this community predominates in important colony environments: Bombella apis. The symbiont is found associated with honey bee larvae, nursing bee crops, and the queen bee digestive tract. I will present work from our lab highlighting the evolution of this microbe, how it protects bees against fungal infection, and how it serves as a nutritional mutualist for larvae. Our work characterizing this microbe has led to direct applications in agriculture, as environmental stressors continue to impact pollinator health.