Beer Hops Beneficial to Honey Bees
Gloria DeGrandi-Hoffman, Fabiana Ahumada, Gene Probasco, Lloyd Schantz. "The effects of beta acids from hops (Humulus lupulus) on mortality of Varroa destructor (Acari: Varroidae)," Experimental and Applied Acarology 58 (December 2012):407-421. DOI: http://dx.doi.org/10.1007/s10493-012-9593-2
Claire Kremen, Neal Williams, Marcelo Aizen, Barbara Gemmill-Herren, Gretchen LeBuhn, Robert Minckley, Laurence Packer, Simon Potts, T'ai Roulston, Ingolf Steffan-Dewenter, Diego Vazquez, Rachael Winfree, Laurie Adams, Elizabeth Crone, Sarah Greenleaf, Timothy Keitt, Alexandra-Maria Klein, James Regetz, Taylor Ricketts. "Pollination and other ecosystem services produced by mobile organisms: a conceptual framework for the effects of land-use change," Ecology Letters 10 (2007): 299-314. DOI: http://dx.doi.org/10.1111/j.1461-0248.2007.01018.x
Colony collapse disorder (CCD) of honey bee (Apis mellifera) colonies reached all-time highs throughout the US between 2007 through 2009. Though several factors have been linked to CCD, varroa mites (Varroa destructor) remain as a major pest of honey bees throughout the world, often forcing commercial beekeepers to insert pesticide-impregnated plastic strips into bee hives to ward off the mites. These plastic strips are effective, but can contaminate the wax honeycomb where bees store food and keep the young, and the mites can develop resistance to the active ingredients used in conventional control strips.
In a recent article published in Experimental and Applied Acarology, researchers from the Carl Hayden Bee Research Center with USDA-Agricultural Research Service teamed with BetaTec Hop Products to test the pesticidal properties of hop beta acids (HBA) against varroa mites. HBA, extracted from the cones of hop plants (Humulus lupulus) used in brewing beer, is known to repel plant-sucking pests and are non-toxic to humans. Honey bees were first exposed to different concentrations of HBA in order to establish a safe exposure baseline and prevent bee mortality. Cardboard strips were then impregnated with low concentrations of HBA (0.5% and 1.0%) and inserted into colony hives. The amounts of HBA tested on the strips were highly lethal to the varroa mites, but did not cause significant mortality to the bees. Though the effects lasted for only a week, HBA seems promising and multiple applications in sync with emerging residual mites may fully control outbreaks.
The use of HBA to combat varroa mites may aid in drastically improving the health, vitality, and robustness of honey bee populations, which provide invaluable ecosystem services as pollinators. The full behavioral changes of mites exposed to HBA are still to be examined, but this study is a great example of nature providing answers to seemingly complex problems, as long as we preserve biodiversity and willingly explore the possibilities… beer in hand.