Reduced density and visually complex apiaries reduce parasite load and promote honey production and overwintering survival in honey bees

• Type of Material: Article
• Authors: Travis L. Dynes, Emory University; Jennifer A. Berry, University of Georgia; Keith S. Delaplane, University of Georgia; Berry Brosi, Emory University; Jacobus De Roode, Emory University
• Language: English
• Date: 2019-05-01
• Publisher: Public Library of Science
• Publication Version: Final Published Version
• Copyright Statement: © 2019 Dynes et al.
• License: Creative Commons Attribution 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1371/journal.pone.0216286
• Title of Journal or Parent Work: PLoS ONE
• ISSN: 1932-6203
• Volume: 14
• Issue: 5
• Start Page: e0216286
• End Page: e0216286
• Grant/Funding Information: Research reported in this publication was supported by the National Institutes of Health (R01-109501, to JCdR, BJB, and KSD), and the National Science Foundation (DGE-1444932, to TLD).
• Keywords: apis mellifera; disease spread; natal colony; health ands survival; honey bee colonies; non-natal colony; apiary management; feral vs domesticated
• Research Categories: Agriculture, Animal Culture and Nutrition

Abstract

Managed honey bee (Apis mellifera) colonies are kept at much greater densities than naturally occurring feral or wild colonies, which may have detrimental effects on colony health and survival, disease spread, and drifting behavior (bee movement between natal and nonnatal colonies). We assessed the effects of a straightforward apiary management intervention (altering the density and visual appearance of colonies) on colony health. Specifically, we established three "high density / high drift" ("HD") and three "low density / low drift" ("LD") apiary configurations, each consisting of eight bee colonies. Hives in the HD apiary configuration were of the same color and placed 1m apart in a single linear array, while hives in the LD apiary configuration were placed 10m apart at different heights, facing outwards in a circle, and made visually distinctive with colors and symbols to reduce accidental drift between colonies. We investigated disease transmission and dynamics between the apiary configurations by clearing all colonies of the parasitic mite Varroa destructor, and subsequently inoculating two randomly-chosen colonies per apiary with controlled mite doses. We monitored the colonies for two years and found that the LD apiary configuration had significantly greater honey production and reduced overwinter mortality. Inoculation and apiary management intervention interacted to affect brood mite levels, with the highest levels in the inoculated colonies in the HD configuration. Finally, foragers were more than three times more likely to drift in the HD apiary configurations. Our results suggest that a relatively straightforward management change-placing colonies in low-density visually complex circles rather than high-density visually similar linear arrays-can provide meaningful benefits to the health and productivity of managed honey bee colonies.