If the recent studies which show
neonicotinoid pesticide toxicity to bumblebee and other wild bees, as well as its addictiveness to bees weren't bad enough, a new nationwide survey just released which covers United States bee losses for the most recent twelve month period from April 1, 2014 to April 1, 2015 reveals an alarming spike in colony loss of 42.1%, up from 34.2% for the preceding year, making this the second highest annual loss recorded since year-round surveys began in 2006. And another worrying result of the survey is much of these losses occurred not in the winter, but in the summer in the hives of commercial beekeepers, which years ago were not the norm. The summer deaths in this period exceed winter deaths for the first time since the surveys began including summer death results, beginning in 2010.
NYT: “We expect the colonies to die during the winter, because that’s a stressful season,” said Dennis vanEngelsdorp, an assistant entomology professor at the University of Maryland who directs the survey for the bee partnership. “What’s totally shocking to me is that the losses in summer, which should be paradise for bees, exceeded the winter losses."
The annual surveys are conducted by the Bee Informed Partnership, which published preliminary results of the most recent survey on May 13, 2015. The preliminary results will be followed by a fuller version which will be published in a peer reviewed journal. Some changes in results may occur in the final version.
Colony Loss 2014 – 2015: Preliminary Results
About two-thirds of the respondents (67.2%) experienced winter colony loss rates greater than the average self-reported acceptable winter mortality rate of 18.7%. Preliminary results estimate that a total of 23.1% of the colonies managed in the Unites States were lost over the 2014/2015 winter. This would represent a decrease in losses of 0.6% compared to the previous 2013/2014 winter, which had reported a total loss estimated at 23.7%. This is the second year in a row the reported colony loss rate was notably lower than the 9-year average total loss of 28.7% (see Figure 1).
Figure 1: Summary of the total colony losses overwinter (October 1 – April 1) and over the year (April 1 – April 1) of managed honey bee colonies in the United States. The acceptable range is the average percentage of acceptable colony losses declared by the survey participants in each of the nine years of the survey. Winter and Annual losses are calculated based on different respondent pools.
Beekeepers do not only lose colonies in the winter but also throughout the summer, sometimes at significant levels. To quantify this claim of non-winter colony mortality of surveyed beekeepers, we have included summer and annual colony losses since 2010/2011. In the summer of 2014 (April – October), colony losses surpassed winter losses at 27.4% (total summer loss). This compares to summer losses of 19.8% in 2013. Importantly, commercial beekeepers appear to consistently lose greater numbers of colonies over the summer months than over the winter months, whereas the opposite seems true for smaller-scale beekeepers. Responding beekeepers reported losing 42.1% of the total number of colonies managed over the last year (total annual loss, between April 2014 and April 2015). This represents the second highest annual loss recorded to date.
Backyard beekeepers, who experienced mostly winter losses, appear to be more affected by the varroa mite than the commercial beekeepers, who more aggressively treat for mites, thus the summer losses of commercial beekeepers appear to be caused by different factors.
The results of the study indicated an uneven death toll from region to region, with some regions being hit by losses of 60% or more. Figure 2 from the survey:
Figure 2: Total annual loss (%) 2014-2015 by state. Respondents who managed colonies in more than one state had all of their colonies counted in each state in which they reported managing colonies. Data for states with fewer than five respondents are withheld.
The study does not offer conclusions about the cause of the losses, and while stresses upon bees are multifactorial, research implicating the class of pesticide known as neonicotinoids as an important factor is accumulating, leading to a
moratorium of the pesticides by the European Union, and the Fish and Wildlife Service of the US, and outright bans by eight states within the U.S., while the U.S. EPA has issued a statement it isn't likely to issue permits for new or expanded usage of the chemicals (a step which environmentalists say is completely inadequate).
Not surprisingly, an entomologist employed by Bayer, one of the leading manufacturers of the neonicotinoid pesticides, while ignoring the increase in summer losses, says the survey results are actually "good news"!
NYT: In a news release, an entomologist at one of the major neonicotinoid manufacturers, Bayer CropScience LP, called the survey results good news because wintertime bee deaths appeared to have stabilized at a lower rate than in the past. The entomologist, Richard Rogers of the company’s Bee Care Center in Research Triangle Park, N.C., said that scientists had yet to establish a normal range for summer bee deaths.