Enhance Honey Bee Safety Around Pesticides
June 1, 2014 In a discussion of honey bee economic impacts, most Americans would universally think of “honey.” National statistics for 2013 indicate that the U.S. had 2.64 million managed honey bee colonies that produced 149 million pounds of honey valued at roughly $317 million (USDA NASS, 2014). Many American might also identify honeycomb waxes as an ingredient supporting a variety of industries like pharmaceuticals, skin care and cosmetics, candles, leather and wood polishes, and artisan crafts like batik clothing and psanky egg decorations. The value of the wax alone (before being converted into these value-added products) is estimated at over $7 million annually (Hansen, 2012).
Fewer Americans would fully recognize the importance of honey bees to agriculture and our nation’s food supply. The agricultural production of roughly one-third of our nation’s diet (fruits, vegetables, berries, and tree nuts) relies on highly efficient pollination efforts by honey bees living in hives managed by commercial beekeepers. These pollination efforts result in increased crop values estimated at $15 billion annually. The demand for honeybee pollination services continue to climb. To put this in perspective, the California almond crop alone requires pollination services from over 1.4 million colonies of honey bees, which is close to 60% of the nation’s managed bee hives (USDA ARS, 2013).
In 2006, America’s beekeepers began reporting mysterious losses of their bee colonies. The hive was still there, but the bees were not. Strangely, hives often still contained the live queen, developing brood, perhaps a small handful of bees, and full stores of accumulated honey and pollen reserves, but tens of thousands of female worker bees had absconded. Conspicuous was the absence of dead honeybees around the hive. These alarming hive losses have been coined colony collapse disorder (CCD). Since 2006, annual winter hive losses have averaged 33%, with one-third of these losses confirmed as CCD-related losses (USDA ARS, 2012).
Beekeepers nationwide have indicated they cannot sustain these kinds of losses over the long term. The national press was quick to point out that the nation’s food supply was at risk by this mysterious honeybee malady. Although it appears that CCD-related hive losses have declined in the past two years, the honeybee research community is careful to avoid calling this a predictable trend.
The exact cause of CCD remains unknown, but substantial research findings indicate that declining honey bee health is caused by a combination of factors that act together to disrupt normal honeybee behaviors which then weaken honey bee hive societies. Many factors that might contribute to CCD have been proposed, and while some have been proven false by research, they still persist as popular postings on social media outlets. See Ellis (2013) for a more detailed discussion of CCD. Possible contributing factors to the CCD disorder are listed below … some have merit and some have less merit:
• Traditional Honeybee Pests/Diseases
A possible contributing factor but these pests/diseases (Varroa mites, hive beetles, American foulbrood, nosema, etc) have been common before CCD occurred in 2006.
• Honeybee Colony Management
Hugely variable across beekeepers, whereby no single practice (managing for honey or for pollination, frequency of hive movement and distance traveled, hive-splitting, supplementary diets, in-hive pest control) has been clearly linked to CCD.
• Genetic Bottleneck: Queen Sources
One concern is that a relatively small number of breeder queens are used to produce millions of queens that are purchased by beekeepers to queen their hives. This practice reduces genetic diversity in honeybee hives throughout the nation, which could make honeybees vulnerable to current and/or new pests/diseases.
• In-Hive Chemical Control Practices
When hives are infested with pests/diseases, many beekeepers apply pesticides as a control measure to save the hive. Research has shown some situations where these pesticides can cause sub-lethal effects to honey bees, even when applied correctly according to label instructions. The common use of miticides to control the destructive Varroa mite is a particular concern. Could these sub-lethal effects be a contributing factor to CCD? Investigations are on-going.
• Chemical Toxins in the Environment
Pesticides are used in agriculture, natural areas, and urban environments to kill pests (insects, weeds, pathogens, etc.) and honeybees collect nectar, pollen, and water from all three environments. There are many routes that can lead to honeybee exposure to toxins. In certain specific scenarios, chemicals not particularly toxic to foraging honeybees are unwittingly carried back to the hive, where they pose more serious danger to developing brood. Some lipophylic (wax-loving) chemicals are known to accumulate within the waxes of the hive structure.
• Genetically Modified Organisms (GMO)
While this factor is popularly discussed in social media outlets, no research data links GMO genetics (say, in the pollen) to CCD. Although many high-value GMO seeds are coated with various pesticides, this is not unique, since many non-GMO seeds are packaged similarly and have been planted long before CCD manifested itself in 2006.
• Varroa Mites
Globally, these mites (and the viruses they carry) are the biggest threat to honeybees, and the fact that they are often controlled with in-hive pesticide applications makes Varroa mites a possible contributing factor to CCD. Yet honeybee colonies with low Varroa mite populations have suffered CCD so currently there is no consistent cause-and-effect relationship between Varroa mites and CCD, although Varroa is definitely linked to compromised honey bee health.
• Honeybee Nutrition
Beekeepers across the nation use many different supplemental nutrition practices, and no single practice is consistently linked to CCD. Reliance on high fructose corn syrup products have been frequently listed in social media outlets, but research has not made this connection to CCD.
• Undiscovered or New Pests/Diseases
A new species of a digestive tract pest (Nosema ceranae) and the recent increase in Israeli Acute Paralysis Virus have attracted attention, but again, their occurrence in hives are not consistently linked to CCD. They are of interest since they could combine with other stressors that work together to reduce honeybee health which could increase susceptibility to CCD.
• Cell Phone Towers
A popular discussion in social media outlets, the idea that cell phone tower signals disrupt honeybee navigation and thus leads to CCD have been largely discounted by researchers. It’s hard to ignore the fact that CCD also occurs in rural areas where cell phone towers are conspicuously absent (USDA ARS, 2013).
The current situation is that the global research community has not found a single “smoking gun” that is consistently linked to CCD. Most agree that CCD is likely caused by a combination of stressors that collectively compromise the complex social organization and biology of honey bees. According to USDA ARS (2013), scientists are focusing on four broad categories in their search for answers to CCD:
1. Pathogens
2. Parasites
3. Management Stressors
4. Environmental Stressors
Many independent studies have shown that the vast majority of pesticides used in agriculture, natural areas, and urban landscapes are safe for the environment and safe for honey bees. However, the in-hive use of pesticides to combat pathogens and parasites, and environmental stressors that might arise from lethal or sub-lethal exposures to a small number of specific pesticides are considered possible contributors to CCD.
The August 2013 announcement by the EPA regarding the release of new pesticide labeling requirements that highlight additional protections for honey bees and other pollinators is consistent with the nation’s concern over CCD incidents. These new labeling requirements are related to the use of neonicotinoid insecticide products. Yet a number of robust research studies that involve honeybee exposure to neonicotinoid products under real-world conditions have not linked neonicotinoids with obvious honey bee health declines.
References
CURES. 2014. Pollinators and pesticide stewardship: Protecting pollinators on farms and urban landscapes. Coalition for Urban/Rural Environmental Stewardship (with Syngenta Crop Protection and Bayer Crop Science) (accessed May 25, 2014).
http://pesticidestewardship.org/PollinatorProtection/Documents/Pollinator%20Brochure%20Oct%202012.pdf.
Ellis, J. 2013. Colony collapse disorder (CCD) in honey bees. University of Florida/IFAS EDIS document DLN=ENY-150. Gainesville, Florida. 5 pp.
http://edis.ifas.ufl.edu/in720.
Ellis, J.D., J. Klopchin, E. Buss, F.M. Fishel, W.H. Kern, C.Mannion, E. McAvoy, L.S. Osborne, M. Rogers, M. Sanford, H. Smith, P. Stansly, L. Stelinski, and S. Webb. 2014. Minimizing honey bee exposure to pesticides. University of Florida/IFAS EDIS document DLN=ENY-162. Gainesville, Florida. 14 pp.
http://edis.ifas.ufl.edu/in1027.
EPA, 2014. Protection of pollinators. Environmental Protection Agency (accessed May 25, 2014).
http://www.epa.gov/pesticides/ecosystem/pollinator/bee-label-info-lrt.pdf.
Hansen, R. 2012. Bees profile. Agricultural Marketing Resource Center (AgMRC), Iowa State University (updated April 2012 by M. Geisler).
http://www.agmrc.org/commodities__products/livestock/bees-profile.
USDA ARS. 2012. Colony collapse disorder progress report. CCD Steering Committee, June 2012. (accessed May 25, 2014).
http://www.ars.usda.gov/is/br/ccd/ccdprogressreport2012.pdf.
USDA ARS. 2013. Honey bees and colony collapse disorder. USDA Agricultural Research Service. (posted Dec. 2, 2013).
http://www.ars.usda.gov/News/docs.htm?docid=15572.
USDA NASS. 2014. Honey. USDA National Agricultural Statistics Service, Agricultural Statistics Board. (released March 21, 2014).
http://www.nass.usda.gov/Publications/Todays_Reports/reports/hony0314.pdf.
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