Colony Collapse Disorder and Honeybee Death Linked with Pesticide Use

The ongoing debate about the cause of colony collapse disorder has finally ended. Mongabay recently reported that “Harvard researchers have re-created the mysterious Colony Collapse Disorder (CCD) in several honeybee hives simply by giving them small doses of a popular pesticide, imidacloprid.”

Bayer pesticide linked with bee death

Imidacloprid is manufactured by Bayer and the company even released a statement to say that the chemical has no effect on colony collapse. However, the Harvard research conclusively shows that the opposite is true.

The cause for colony collapse has been eluding scientists for many years. However, two studies that came out in Science showed a close link between neonicotinoid pesticides, of which imidacloprid is one. According to Mongabay:

Past research has shown that neonicotinoid pesticides, which target insects’ central nervous system, do not instantly kill bees. However, to test the effect of even small amounts of these pesticides on western honeybees (Apis mellifera), Harvard researchers treated 16 hives with different levels of imidacloprid, leaving four hives untreated. After 12 weeks, the bees in all twenty hives—treated and untreated—were alive, though those treated with the highest does of imidacloprid appeared weaker. But by 23 weeks everything had changed: 15 out of the 16 hives (94 percent) treated with imidacloprid underwent classic Colony Collapse Disorder: hives were largely empty with only a few young bees surviving. The adults had simply vanished. The hives that received the highest doses of imidacloprid collapsed first. Meanwhile the five untreated hives were healthy.

Harvard study links pesticide use with colony collapse

Scientists in the past have been cautious about the connection between pesticides and honey bee collapse. However, lead author of the Harvard report, Chensheng (Alex) Lu has dismissed all caution and has made it clear that:

There is no question that neonicotinoids put a huge stress on the survival of honey bees in the environment. The evidence is clear that imidacloprid is likely the culprit for Colony Collapse Disorder via a very unique mechanism that has not been reported until our study.

Beekeepers started feeding bees with high fructose corn syrup and this did not have an effect on bees until 2004-2005 when US corn crop began to be sprayed with imidacloprid. The first recorded outbreak of colony collapse occurred a year later.  According to Lu even, small amounts like 20 ppb of the chemical was enough to lead to full blown CCD within 6 months.

Studies from UK and France support Harvard study’s conclusion

Just before the Harvard study was released, two studies from the UK and France also linked neonicotinoid pesticides to CCD. The UK study exposed bumblebees to small doses of imidacloprid and places the bees in an enclosed natural setting. After six weeks, the team found that the nests of the exposed bees weighed less than that the control group. The French team glued microchips to free-ranging honeybees and discovered that the bees that were exposed to pesticide were three times more likely not to return from foraging. This proved that the chemical also interfered with the bees’ homing abilities.

Policy change needed to prevent honeybee extinction

Although the pesticide does not kill bees instantly, it does cause colony collapse over time. In fact, it is more dangerous because it does not kill instantly as there is no way of estimating exactly how many bees are affected. Bees are a vital cog in the economy, and the economic value of honeybees in the US alone is said to be $8-12 billion. Policy makers need to now examine the effect of pesticides more carefully and look at long-term effects rather than just short-term to protect the honeybee from extinction.

Image Credit: Honeybee sucking nectar, Severnjc, Wikimedia Commons 

Akhila is the Founding Director of GreenDen Consultancy which is dedicated to offering business analysis, reporting and marketing solutions powered by sustainability and social responsibility. Based in the US, Europe, and India, the GreenDen's consultants share the best practices and innovation from around the globe to achieve real results. She has previously written about CSR and ethical consumption for Justmeans and hopes to put a fresh spin on things for this column. As an IEMA certified CSR practitioner, she hopes to highlight a new way of doing business. She believes that consumers have the immense power to change 'business as usual' through their choices. She is a Graduate in Molecular Biology from the University of Glasgow, UK and in Environmental Management and Law. In her free-time she is a voracious reader and enjoys photography, yoga, travelling and the great outdoors. She can be contacted via Twitter @aksvi and also

10 responses

  1.  Corn has been poisoned through genetic engineering. Corn was genetically modified to produce its own insecticide, and sprayed on corn that was only used on animal feed. But through cross-fertilization is spread to almost all the corn on the planet, though rare genetic transfer between species. In a few decades may make any plant, that doesn’t rely on helpful insects, more insect resistant to them.

    It is giving Mexicans who survive on mostly corn allergies. Sick bees fly away from the hive to avoid spreading infection, but farmers feed bees corn syrup when there are not enough flowers around.. Urban bees can find spilled soda, and if they get back to the hive before feeling a little sick, start poisoning the hive. One black hole created by the Large Haddon Collider shouldn’t alarm us because without enough gravity to react with other mater for millions of years unless the LHC is creating millions of them slowly drifting toward each other at the center of the planet

    Everyone is missing the horror. Don’t bother to buy organic vegetables unless grown from 10 year old seeds in an airtight greenhouse.

    From Richard Kane

      1. You scared him away, damnit. He was about to let us in on the secret of LHC. Don’t you remember the X-Files?? There were bees there, too. LHC, Bees, and Aliens. That’s the truth.

  2. Sorry, Akhila Vijayaraghavan, and
    Tawster about the rush.

    All corn is genetically modified to
    contain insecticide because of cross-pollination,

    Apparent sick bees staying away from
    the hive seems to be an overwhelming trait even if born sick. If this
    changes commercial hives, with a lot of antibiotics and bee doctors
    around, this would be a manageable problem. But what about wild bees
    that like to sip on soda pop? It is a potential time bomb, if sick
    bees start retuning to the hive. This should remind us that there are
    other areas where certain hopefully only potential, mistakes may
    never be corrected. One theory that is very credible rather than only
    believed by a few researchers is that there may be a micro black hole
    in most stellar objects that are so inert as that almost all of them
    won’t consume that stellar object before it is destroyed some other

    By the way I read about this bee
    problem at Reader Supported News that removed it from its front page
    as old news, and can be reached only if the link memory is already on
    ones computer,

    1. See:, or other hits that come up when searching for “colony collapse disorder update 2012”

  3. That evidence points to pesticides should not surprise any of us. We developed a fondness for pesticides, herbicides, etc. primarily for the convenience they gave us over more labor-intensive food production methods. “The magic of chemical solutions” seemed impressive. Besides, a rapidly developing post-WW2 chemical industry needed markets. Advertising reassured us – this stuff “used as directed of course” will never, ever, “come back to bite us”. I’m pretty sure in the early days even the developers/marketers believed this. Now, (generally in the world of chemical marketers, including for-human pharmaceuticals) we eventually discover a trail of emails and internal company documents that suggest marketing trumps good and scrupulously honest science – every time.

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