Colony Collapse Disorder Killing Honeybees Is Caused by Pesticides

Colony Collapse Disorder

Colony Collapse Disorder (CCD), which wipes out entire beehives, is a bit like climate change in the sense that scientists have worked hard to pinpoint a definitive cause. Both phenomena are head-scratchers that leave some people wondering if they are even real.  A new study has found strong evidence that pesticides are the cause of Colony Collapse Disorder, which is real, and really killing millions of honeybees.

This particular bee-killing phenomenon has alarmed the scientific community because as honeybee colonies collapse, so do many other vital systems. It is common knowledge that the honeybee’s specific job in the natural order of things is to pollinate plants so that both organisms can thrive.  What people may not know is just how important that job is—honeybees pollinate an estimated $30 billion worth of crops in the U.S. alone. That is a lot of food.

Aside from industry losses, there is another important reason CCD has created such a buzz.  If the world were to lose most or all of its honey bee population, plants would become extinct.  Einstein speculated that if these two things happened, humans would also be extinct, in a matter of just a few years.

Since 2005 when beekeepers first began reporting mass losses, CCD has been thought to be the cause of death for over 10 million beehives.  There have been a lot of different theories behind the mass die-offs, from pesticides in general to parasitic mites to cell phone tower emissions.  Researchers that have devoted themselves to getting to the bottom of the real cause know that some of these factors are certain causes of honeybee disease and death, but there are very specific signs that hint at CCD as the culprit.

While disease may kill off some bees, leaving them dead in a hive for a beekeeper to find, a sign of CCD is that adult bees “disappear” from the colonies, leaving everything behind including honey and the queen.  While it is completely normal for honeybees to leave their hive for the winter, they are systematically programmed to return.  With CCD, colonies never pick back up when the weather warms up.  Another strange symptom of CCD is that other honeybees and insects ignore the empty hives even though they contain loads of honey and other organic matter that they are known to eat.

The latest study, conducted by researchers at Harvard, has produced some interesting evidence that seems to indicate that Colony Collapse Disorder is caused by pesticides, specifically a class of insecticides known as neonicotinoids.  Neonicotinoids are neuro-active pesticides that are chemically similar nicotine, and they are first new class of insecticides introduced in the last 50 years.  Fortunately, this class of bug chemicals has been widely used because they produce much lower levels of toxicity—in mammals.  Unfortunately for other animals, particularly birds and bees, that is not the case.  For a few years, the scientific community has been linking neonicotinoids to CCD, citing evidence that the chemicals disrupt honey bee immune systems and neurological functioning.

Harvard researchers teamed up with the Worcester County Beekeepers Association in Massachusetts to track the health of18 bee colonies throughout central Massachusetts from October 2012 through April 2013. Twelve of the colonies were treated with different types of neonicotinoid pesticides, while six colonies were not treated with anything.  All of the bee colonies declined through the beginning of winter, as they are supposed to naturally.  As the winter progressed and the weather began to warm again, bee populations in all six control colonies began to return, while half of the neonicotinoid-treated colonies completely vanished.  Only one control colony died off, but dead bees were found in and around the hive, suggesting a parasitic disease as the culprit, not CCD.

These results reaffirm suspicions that CCD is primarily a matter of pesticide use, but study authors are also being careful to reinforce the notion that pesticides do not work alone to cause some of the most dramatic die-offs.  For instance, in this study, the 12 hives treated with pesticides only lost half to CCD.  In an earlier study in 2012, conducted by the same research team, the deadly mass exodus began earlier in the winter and claimed 94 percent of the bees studied as opposed to 50 percent.  The winter of 2011 and 2012 was long and cold, and researchers have speculated that colder temperatures combined with neonicotinoid use work together to create more severe CCD effects.

With the 2013-2014 winter just fading out, it will be interesting to see what kind of buzz will be associated with CCD, and whether further studies will be conducted to flesh out whether pesticides are causing the Colony Collapse Disorder that is killing honeybees.

By Erica Salcuni


University of Florida


2 Responses to "Colony Collapse Disorder Killing Honeybees Is Caused by Pesticides"

  1. Bill   August 5, 2014 at 6:13 pm

    Honey and Honeybee populations dropping because of colony collapse disorder is frightening to me.

    Is this from the transportation of the bees or monocultures or is it being caused by pathogens and parasites or even electromagnetic radiation and a proliferation of genetically-modified crops?

    I am betting that it is mostly from Neonicotinoids which are a popular insecticide used and that is being tracked as being closely related in area to collapsing bee colonies

  2. Laura Breyer   May 12, 2014 at 12:33 pm

    Canada uses neonicotinoids on all of its conventional canola crop and has no incidence of CCD. Australia uses neonicotinoids and has no CCD. Eric Mussen, UCD apiculture specialist, has said there is no credible evidence connecting neonicotinoids to CCD. What Harvard study are you citing? If you consider yourself a journalist, consider the harm you do by misdirecting attention from finding the real cause of CCD.

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