From http://www.ars.usda.gov/News/docs.htm?docid=15572:
Quote:
In October 2006, some beekeepers began reporting losses of 30-90 percent of their hives. While colony losses are not unexpected, especially over the winter, this magnitude of losses was unusually high.
The main symptom of CCD is very low or no adult honey bees present in the hive but with a live queen and no dead honey bee bodies present. Often there is still honey in the hive, and immature bees (brood) are present. Varroa mites, a virus-transmitting parasite of honey bees, have frequently been found in hives hit by CCD.
This is not the first time that beekeepers are being faced with unexplained losses. The scientific literature has several mentions of honey bee disappearances?in the 1880s, the 1920s, and the 1960s. While the descriptions sound similar to CCD, there is no way to know for sure if those problems were caused by the same agents as CCD.
There have also been unusual colony losses before. In 1903, in the Cache Valley in Utah, 2000 colonies were lost to an unknown "disappearing disease" after a "hard winter and a cold spring." More recently, in 1995-96, Pennsylvania beekeepers lost 53 percent of their colonies without a specific identifiable cause.
In June 2007, ARS and the National Institute of Food and Agriculture (NIFA), USDA's extramural research grants agency, co-chaired a workshop of scientists and stakeholders to develop a Colony Collapse Disorder Action Plan. This plan identified areas where more information was needed and developed a research priority list for additional research projects related to finding the cause/causes of CCD.
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Declines in honey bee colony health were exacerbated in the 1980s with the arrival of new pathogens and pests. The arrival of Varroa and tracheal mites into the United States during the 1990s created additional stresses on honey bees.
Colony losses from CCD are a very serious problem for beekeepers. Annual losses from the winter of 2006-2011 averaged about 33 percent each year, with a third of these losses attributed to CCD by beekeepers. The winter of 2011-2012 was an exception, when total losses dropped to 22 percent.
A 1-year drop is too short a time period to count as definitive improvement in honey bee colony survivorship. At least 2 to 3 years of consistently lower loss percentages is necessary before it is possible to be sure that CCD is on the decline.
The decrease in colony losses could be due to a number of different factors, among them:
1. The 2011-2012 winter was unusually warm and could have contributed to higher colony survival rates, although there is no scientific research connecting warmer winter weather and CCD. January 2012 ranks as the fourth warmest January in U.S. history, according to NOAA.
2. Research from ARS and other institutions has provided new management recommendations that beekeepers have begun to adopt. For example, it is now recommended that beekeepers feed honey bees more protein during times of nectar shortage such as during times of drought or in the winter. As part of this, ARS has developed a new bee diet, Megabee, now available to beekeepers. The feeding of supplemental nutrients may help to decrease winter colony losses.
3. Some diseases are naturally cyclical, and CCD could be at the point where its cause/causes have passed their peak. Or it is possible that colonies that survive could be developing a natural resistance to overcome the unknown cause/causes of CCD. Unfortunately, there is no scientific proof for either of these at this time.
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Research Directions
Scientists are looking in four general categories for the cause/causes of CCD:
1. Pathogens: Among others, scientists are considering Nosema (a pathogenic gut fungi), Israeli Acute Paralysis Virus, and possibly unknown pathogens as possible culprits in CCD. ARS research has indicated that no one pathogen of any class directly correlates with the majority of CCD incidents. Rather, a higher total pathogen load of viruses and bacteria correlates more directly with CCD than any one specific pathogen.
2. Parasites: Varroa mites are often found in honey bee colonies that are affected by CCD. It is not known if the Varroa mites are directly involved or if the viruses that Varroa mites transmit (similar to the way mosquitoes transmit the malaria virus) are a factor in causing CCD.
3. Management stressors: Among the management stressors that are possible contributors to CCD are poor nutrition due to apiary overcrowding and increased migratory stress brought on by the honey bees being transported to multiple locations across the country.
4. Environmental stressors: Such stressors include the impact of pollen/nectar scarcity, lack of diversity in nectar/pollen, availability of only pollen/nectar with low nutritional value, and limited access to water or access only to contaminated water. Stressors also include accidental or intentional exposure to pesticides at lethal or sub-lethal levels.
A survey of honey bee colonies revealed no consistent pattern in pesticide levels between healthy and CCD-affected colonies when pollen, bees, and beeswax were tested for the presence of 170 pesticides. The most commonly found pesticide in that study was coumaphos, which is used to treat honey bees for Varroa mites.
The pesticide class neonicotinoids (clothianidin, thiamethoxam, and imidacloprid) has been accused of being the cause of CCD. The neonicotinoids were developed in the mid-1990s in large part because they showed reduced toxicity to honey bees, compared with previously used organophosphate and carbamate insecticides.
In 2008, Germany revoked the registration of the neonicotinoid clothianidin for use on seed corn after an incident that resulted in the die-off of hundreds of nearby honey bees colonies. Investigation into the incident revealed that the die-off was caused by a combination of factors, including the failure to use a polymer seed coating known as a "sticker": weather conditions that resulted in late planting of corn while nearby canola crops were in bloom, attracting honey bees; use of a particular type of air-driven equipment used to sow the seeds, which blew clothianidin-laden dust off the seeds and into the air as the seeds were ejected from the machine into the ground; dry and windy conditions at the time of planting, which blew the dust into the nearby canola fields where honey bees were foraging; and a higher application rate than had been authorized was used to treat for a severe root worm infestation.
Several studies that reported a negative impact on honey bees by neonicotinoids relied on large, unrealistic doses and gave bees no other choice for pollen, and therefore did not reflect risk to honey bees under real world conditions. Nor have the studies demonstrated a direct connection or correlation to CCD.
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While a number of potential causes have been championed by a variety of researchers and interest groups, none of them have stood up to detailed scrutiny. Every time a claim is made of finding a "smoking gun," further investigation has not been able to make the leap from a correlation to cause-and-effect. Other times, not even a scientific correlation has been demonstrated in the study claiming to have found "the cause" of CCD.
Researchers have concluded that no one factor is the cause of CCD. Most likely, CCD is caused by multiple factors. It is not possible to know at this time if all CCD incidents are due to the same set of factors or if the factors follow the same sequence in every case.
One explanation for CCD being studied is that a perfect storm of environmental stresses may unexpectedly weaken colonies, leading to collapse when the colonies are exposed to the additional stress of a pathogen, parasite, and/or pesticide. Stress, in general, compromises the immune system of bees (and other social insects) and may disrupt their social system, making colonies more susceptible to disease.
Studies are being conducted by ARS scientists and collaborators to look at the combined impact of two or more factors on honey bees?most recently the impact of exposure to the neonicotinoid imidacloprid and Nosema. While the dual exposure indicated some sublethal effects on individual honey bees, the overall health of the colony did not show an adverse effect.
10 Jul 2014, 12:27 pm
The pesticide companies want to give you cancer,then the pharmaceutical companies get to cash in on your illness.The damn poison merchants.
