Effects of Carbon Dioxide on Hemolymph and Brain Proteomes in Honey Bee Workers (Apis mellifera L.)

Carbon dioxide (CO₂) is essential in beekeeping practices but its optimal dosage and physiological effects on honey bees remain unclear. This study examined CO₂ tolerance and molecular responses across three developmental stages: newly emerged, nurse, and forager bees, using gradient exposure and proteomic analysis. Newly emerged bees demonstrated the highest CO₂ tolerance. Hemolymph and brain exhibited distinct responses: the cytochrome P450 pathway dominated in hemolymph, while the brain displayed stage-specific strategies. Newly emerged bees activated metabolic reorganization and clearance pathways. Nurse bees strengthened antioxidant defenses, while foragers enhanced amino acid metabolism to produce antioxidant precursors. All stages showed role-specific energy metabolism reprogramming to meet increased post-exposure demands. These findings provide critical data and theoretical foundations for honey bee colony management, transportation, and handling practices. The results also contribute valuable insights to the fundamental biology of other insects.