A longitudinal study of queen health in honey bees reveals tissue specific response to seasonal changes and pathogen pressure

Authors: Copeland, Duan; Ricigliano, Vincent; Mott, Brendon; Kortenkamp, Oliver; Erickson, Robert; GORROCHATEGUI-ORTEGA, J. - University Of Basque Country; Anderson, Kirk

Submitted to: Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/4/2024
Publication Date: 4/18/2024
Citation: Copeland, D.C., Ricigliano, V.A., Mott, B.M., Kortenkamp, O.L., Erickson, R.J., Gorrochategui-Ortega, J., Anderson, K.E. 2024. A longitudinal study of queen health in honey bees reveals tissue specific response to seasonal changes and pathogen pressure. Scientific Reports. 14. Article 8963. https://doi.org/10.1038/s41598-024-58883-1.
DOI: https://doi.org/10.1038/s41598-024-58883-1

Interpretive Summary: Problem: Honey bee queens are essential for the survival and success of their colonies, but their health is under threat, particularly during tough winter months. Accomplishment: In our study, we analyzed the gut bacteria, gene activity, and disease exposure in honey bee queens overwintering in warmer climates. We discovered significant changes in gene expression and bacterial composition. Our research identified a crucial relationship between high pathogen pressure and reduced reproductive health in queens. Contribution to Solving the Problem: Our findings offer insights into the relationship between pathogens, metabolism, and immune responses in honey bee queens. This knowledge contributes to a deeper understanding of queen health and resilience. By understanding these dynamics, we can develop better approaches to safeguarding queen bees, crucial for maintaining healthy bee populations and, by extension, global ecosystems and agriculture.

Technical Abstract: The health of honey bee queens is crucial for colony success, particularly during stressful periods like overwintering. To accompany a previous longitudinal study of worker health, we explored niche-specific gut microbiota, host gene expression, and pathogen prevalence in honey bee queens overwintering in a warm southern climate. We found differential gene expression and bacterial abundance with respect to various pathogens throughout the season. Biologically older queens had larger microbiotas, particularly enriched in Bombella and Bifidobacterium. Both Deformed Wing Virus A and B subtypes were highest in the fat body tissue in January, correlating with colony Varroa levels, and Deformed Wing Virus titers in workers. High viral titers in queens were associated with a decrease in vitellogenin expression, suggesting a potential trade-off between immune function and reproductive capacity. Additionally, we found a complex and dynamic relationship between these viral loads and immune gene expression, indicating a possible breakdown in the coordinated immune response as the season progressed. Our study also revealed a potential link between Nosema and Melissococcus plutonius infections in queens, suggesting that seasonal opportunism is not confined to just workers. Overall, our findings highlight the intricate interplay between pathogens, metabolic state, and immune response in honey bee queens. The data is associated with simultaneous emphasizing the need for a social and longitudinal approach to understanding queen health and resilience.