Impacts of short-term queen banking on virus infection and immune-oxidative stress responses in honey bee queens

Queen banking is a common management practice primarily in commercial beekeeping or queen-producing operations, used to either temporarily store surplus mated queens during beekeeping season or to ensure their availability in the early spring. However, the effects of this practice on viral infection dynamics and queen physiology (immune and stress response) are not well understood. To address this knowledge gap, we examined the dynamics of viral infection, oxidative stress, and immune responses in virgin and mated queens during a three-week spring banking period. We performed qRT-PCR to quantify four common honey bee viruses (DWV-A & B, BQCV, and LSVs), as well as three immune genes ( dicer-like , hymenoptaecin , defensin-1 ) and three stress-related genes ( CuZnSOD , catalase , and vitellogenin ). Viral loads in queens and their attendant workers stayed mostly stable, indicating that short-term banking is not a major route of virus proliferation. However, gene expression analysis revealed that immune and stress responses varied significantly between weeks, with a general decline by the third week—possibly due to reduced immunocompetence. Unlike mated queens, virgin queens in bank colonies exhibited higher CuZnSOD and catalase expression, lower vitellogenin expression, and higher mortality, suggesting greater sensitivity to banking, likely due to differences in pheromone profiles and the subsequent feeding and care from attendants. Stress from confinement and social crowding, rather than viral activity, primarily influences queen physiological responses during banking. These responses also appear to depend on the reproductive status of the queen, which may modulate interactions between viral infection and host gene expression. These findings offer new insights into how short-term queen banking impacts viral infection and physiological responses, with potential implications for queen quality and post-storage performance.