Honey bee colony performance and health are enhanced by apiary proximity to US Conservation Reserve Program (CRP) lands

Authors: Ricigliano, Vincent; Mott, Brendon; Maes, Patrick - University Of Arizona; Floyd, Amy - University Of Florida; Fitz, William - University Of Florida; Copeland, Duan; Meikle, William; Anderson, Kirk

Submitted to: Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/22/2019
Publication Date: 3/20/2019
Citation: Ricigliano, V.A., Mott, B.M., Maes, P., Floyd, A.S., Fitz, W., Copeland, D.C., Meikle, W.G., Anderson, K.E. 2019. Honey bee colony performance and health are enhanced by apiary proximity to US Conservation Reserve Program (CRP) lands. Scientific Reports. 9:4894. https://doi.org/10.1038/s41598-019-41281-3.
DOI: https://doi.org/10.1038/s41598-019-41281-3

Interpretive Summary: The US Conservation Reserve Program (CRP) incentivizes reassignment of marginal croplands to long-term conservation covers in exchange for annual payment to private landowners. Recent evidence suggests that the CRP has a positive impact on landscape suitability for supporting honey bee apiaries. We tested the effects of CRP landscapes versus agriculturally intensive landscapes on honey bee colony physiology. Using a pooled-sampling method to overcome individual variation, we monitored colony-level molecular biomarkers during critical pre- and post-winter time points. Exposure of colonies to either CRP or agriculturally intensive foraging environments revealed that major categories of bee physiology (nutrition, oxidative stress resistance, and immunity) were significantly impacted by landscape. In particular, colonies exposed to CRP landscapes exhibited improved performance and elevated gene expression that was indicative of augmented health status. Our study highlights the utility of colony-level molecular diagnostics as a means of assessing landscape suitability for honey bees. Furthermore, removal of land from agricultural production and enrollment into the CRP may improve pollinator health.

Technical Abstract: Honey bee colony performance and health are intimately linked to the foraging environment. Recent evidence suggests that the US Conservation Reserve Program (CRP) has a positive impact on landscape suitability for supporting honey bee apiaries. However, relatively little is known about the influence of habitat conservation efforts on bee colony physiology. A step towards identifying specific factors that influence honey bee health at the colony level incorporates longitudinal monitoring of physiology across divergent landscapes. Using a pooled-sampling method to overcome individual variation, we monitored colony-level molecular biomarkers during critical pre- and post-winter time points. Exposure of colonies to either CRP or agriculturally intensive foraging environments revealed that major categories of bee physiology (nutrition, oxidative stress resistance, and immunity) were significantly impacted by landscape. Colonies exposed to CRP landscapes exhibited improved performance and higher mRNA levels of vitellogenin (vg), a nutritionally regulated protein with central storage and regulatory functions. Mirroring vg levels, gene transcripts encoding antioxidant enzymes (catalase, superoxide dismutase, glutathione S-transferase) and immune-related proteins (abaecin, apidaecin, defensin-2, lysozyme-2) were typically higher in colonies exposed to CRP landscapes. Our study highlights the utility of colony-level molecular diagnostics as a means of assessing landscape suitability for honey bees, which can inform future land-use and commercial beekeeping management decisions.