For a period of two years Bayer researchers and external contract scientists in Canada partnered with apiarists to study factors that may negatively impact honey bee health. The initial results show two aspects: Viruses are ubiquitous and also no correlation between bee health and neonicotinoid use could be established.
The Canadian Sentinel Hive Study took place in Eastern Canada from 2013 to 2015 and was extended to Western Canada from 2014 to 2015. All together the experts observed 36 managed hives in Ontario, Quebec, Manitoba, Saskatchewan and Alberta. The objective of both studies was to monitor changes in honey bee health and population dynamics by taking quantitative and qualitative assessments over time. Study hives were positioned near neonicotinoid seed-treated corn, soybean, or canola fields to expose them to an environment that might be considered high risk. Consequently, surveillance and monitoring of landscape and field features and agricultural practices formed an important component of these studies. The researchers periodically sampled in-hive products including honey, nectar, wax, and pollen to determine the timing, frequency and magnitude of exposure to agrochemicals – particularly those used in corn and canola production. The goal was to determine and describe correlations of colony health with local environmental and management impacts, including agricultural practices.
Prior to seeding, each hive was subject to a colony condition assessment (CCA) to obtain information on the presence and health of the queen and the brood. Also the in-hive products were precisely documented, as well as the presence of visible symptoms of parasites, pathogens, and diseases. A total of five CCAs were performed throughout each season.
The full evaluation of the Sentinel Hive Studies has not been completed, but the first results are significant: “No correlation between the presence of neonicotinoids and hive health issues could be established,” states Dr. John Purdy, a contract researcher and independent study director of the Eastern Sentinel Hive Study. He also commented on the biggest problem: “All adult bee samples collected, particularly impaired bees at the hive entrance, were infected with at least one virus, while over 50 percent of samples tested positive for three or more viruses.” Among others the hives were tested for Varroa destructor, tracheal mites, Nosema and American and European foulbrood. The most wide spread virus was the sacbrood virus (SBV). The major cause of colony decline in this study was swarming, with loss of the queen and a large fraction of the worker population. The remnant hive was weak and vulnerable to looting by other bees.
The study in Western Canada identified that availability and quality of nutrition play a significant role in honey bee colony health: “Using palynological assessments where we identify the origin of bee-collected pollen grains, we were able to observe a clear shift from tree pollen in the spring to mustards and clovers in the summer. Where bees faced a cold, wet spring that prevented them from collecting pollen, hive build-up was delayed, and in both studies we clearly saw that proximity is not the main driver for pollen source selection,” explains Maryam Sultan, Bayer CropScience Bee Health Associate and Sentinel Hive Study monitor. Now, further studies are being planned to better understand the nutritional requirements for healthy bee colonies and those being moved for the purpose of providing pollination services. The Canadian Sentinel Hive Studies have strengthened the ability of Bayer to proactively engage with stakeholders in future collaborative bee health initiatives.
Find out about the Ontario Beekeeper’s Association