Bacterial supplementation shapes honey bee gut microbiota and host metabolism under controlled and field conditions

Abstract

Honey bees are essential pollinators whose health is influenced by their gut microbiome. Probiotic applications aimed at improving gut health have been proposed, yet outcomes remain inconsistent and vary across settings. Results from laboratory experiments often differ from those observed under field conditions, making it difficult to understand the complex dynamics of eusocial insect colonies. Here, we evaluate honey bee gut-derived bacterial supplementation across controlled, semi-controlled, and field settings using bacterial profiling, proteomic, and metabolomic analyses. We demonstrate that bacterial-supplemented groups consistently reshape gut community composition and modulate host physiological processes, but in a context-dependent manner. These results provide a unified understanding of how microbial interventions function at colony and individual levels, guiding the rational design of probiotic strategies to support honey bee health under realistic conditions.