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Colony Collapse Disorder: Science and Pseudoscience

Donate Everyone loves to point the finger at the cause of Colony Collapse Disorder; here's what we actually know.  

by Brian Dunning

Filed under Environment

Skeptoid Podcast #524
June 21, 2016
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Colony Collapse Disorder: Science and Pseudoscience

Today we're going to put on our beekeeper's suit, trudge on out to our apiary, and have a look at our beehives. If we're lucky, all the bees will still be there. But since 2006, an increasing number of beekeepers have been having the opposite experience. The bees have been disappearing, and disappearing fast. It's called Colony Collapse Disorder (CCD), and as hard as the scientists have been working to explain it, the pseudoscientists have been working at making up nonsense explanations, usually to further some agenda. This week we're going to put our hive minds to work to separate what's true from what's not, and see if there's anything we can do to save the bees.

In every normal season, beekeepers see some percentage of their colonies die. These are called overwintering losses, and they're a natural and expected part of bee colonies. New bees are born each year to take their place. But beginning in 2006, beekeepers in both the Americas and Europe saw overwintering losses in much larger proportions: bees simply never returned to the hive. The queen and the honey and the young bees would be in there, but sometimes no worker bees at all. The cause was not known, and it came to be called Colony Collapse Disorder.

Such die-offs of bees are not new. One famous case happened in the UK in 1906; another happened in the US in 1918 and 1919. But the current event is unprecedented, having lasted a decade already. In 2015, data looked promising as we'd enjoyed two years of colony growth, but when the 2015 data came out in 2016 we found an enormous 12% loss. We are not out of the woods yet, and we still don't fully understand the causes or the solution.

The most attention has been focused on a class of pesticides called neonicotinoids, and one in particular called imidacloprid. They're commonly called neonics for short. In 2013, the European Union limited the use of three popular neonics — to the great consternation of the farmers who depend on them — but so far the EU has not seen any benefit from having done so. Over the years since 2006, neonics have been in and out as the culprit. Predictably, the pro and con camps have condensed into the two groups who naturally favor or oppose non-organic pesticides: the pesticide producers, and the organic lobby.

And as we see so often, as soon as ideology enters an equation, all kinds of wacky misinformation gets invented by those hoping to leverage a real-world misfortune and use it to promote their ideology. The Organic Consumers Association, perhaps the world's most active anti-biotech lobbying group, was among the first and most vocal to jump on this bandwagon. They recently summarized their claims in a 2014 article that although neonics are the main culprit, the herbicide Roundup and genetically modified crops are to blame as well. Other activists have pointed to cell phone signals, climate change, and even beekeeping practices. Let's take a look at some of these.


A brand name for the much-maligned herbicide glyphosate is frequently accused of being responsible for just about anything bad, but no plausible science suggests that it might be involved in CCD. For one thing its mechanism operates on a plant enzyme not present in bees; and for another thing its use does not correlate with CCD either geographically or temporally. Cross this one off your list.


Many anti-biotech sources claim that bees pollenating GMO crops become poisoned by the act and die. There is neither evidence nor plausible foundation behind this belief. In addition, it also lacks geographical and temporal correlation. Cross it off your list too.

Cell Phone Signals

As Skeptoid listeners and others with basic science literacy know, radio signals are non-ionizing radiation, meaning they don't have enough energy to change the orbits of electrons, and thus can't trigger chemical reactions. So radio is harmless to bees and everything else that consists of living tissue.

But citing the longstanding public concern about cell phone signals, three German scientists did a study testing the ability of bees to find their hives when either exposed or not exposed to a particular radio base station. Their study found no difference; but as the media is wont to do, it was completely misreported to make it sound like the study proved cell phone signals caused CCD. The researchers have repeatedly said their study had nothing to do with either cell phones or CCD. One of the authors told the Associated Press there was "No link between our tiny little study and the CCD phenomenon... Anything else said or written is a lie." But the damage had already been done, and it remains a fringe belief today.

Hardcore Woo

You can go way out to the fringe and find increasingly bizarre proposals to explain CCD. Richard Hoagland, the conspiracy theorist who promoted the idea of the "Face on Mars", believes it is caused by a pseudoscientific theory of the universe called torsion physics, invented in the 1980s by Russian cranks. This is a fair sampling of how weird some of the claims can get.

So now let's look at the real causes of CCD.

The Real Causes

The best way to do this is to quote from the Executive Summary on this year's Honey Bee Health Action Plan from the US Department of Agriculture, which has been regularly updated throughout the current crisis:

U.S. honey bees have been under attack by a large number of stressors, including invasive mites (Varroa and tracheal), insect pests (small hive beetle), pathogens (Nosema species, American foulbrood, chalk brood, Israeli acute paralysis virus, black queen virus and numerous other viruses), lethal and sublethal pesticide exposure, Africanization of managed colonies, nutritional deficiencies due to lack of forage and/or forage diversity, genetic factors and other problems. Each of these problems has put additional pressure on honey bee survival and has contributed to increasing managed colony losses.

That's at least seven major causes, all seven of which are multifaceted. For more information on these, I highly suggest downloading and reading this free PDF report. It gives a summary of each, more detailed information on each, and most importantly, it describes the action plan for each and makes recommendations for both beekeepers and consumers on what they can do to reduce the severity of the problem.

But since such a disproportionate amount of attention falls on pesticides, and neonics in particular, let's talk about that in a little more depth.


Without much doubt, sufficient evidence exists that pesticides do contribute to the overall picture of CCD. But it's not thoroughly understood. Most of the action plan recommendations in the USDA report suggest more studies to learn what pesticides at what dosages may actually produce what effect, and find best management practices to balance that with the needs of agriculture. The relationship between bees and agriculture is deep and more complex than many laypeople realize.

The question of the role of neonics in CCD has not been helped by the fact that the most public proponent of the theory has been Harvard environmental scientist Chensheng "Alex" Lu, who published the first studies demonstrating the effect, and continues to be at the forefront of the fight to pin CCD on neonics. The problem is that Lu's work has been widely discredited (see here, here, and here for starters) for being based more on his personal ideology than on science, and that it's been part of a career-long crusade against all non-organic pesticides, and unscientific promotion of the health benefits of organic diets. What Lu did was to take the food given to honeybees and contaminate it with high levels of neonic insecticides, absurdly higher than bees could ever be exposed to in the real world, which (quite naturally) was highly destructive to them, as we'd expect. Harvard's powerful press release machine went into action, and neonics as the main cause of CCD became a widely held belief worldwide — by the general public, if not by the scientists.

A common theme is that Lu and other biotech opponents like the Consumer Organics Association tend to always cite Silent Spring, the famous book by Rachel Carson that first drew a link between the pesticide DDT and bird deaths. It's a non-sequitur since the book had nothing to do with bees, but the cautionary tale sounds compelling and is repeated in virtually every anti-neonics article.

Obviously insecticides are not helpful to bees, and nobody's arguing that they are. But so far as we know, the amount that bees can reasonably be exposed to during the normal course of their activities should be generally safe. However, necessarily, neonics and other agricultural chemicals will rightly continue to be a focus of researchers. The theoretical ability of neonics to be a major contributor to CCD is absolutely plausible. If it is a contributor, as some evidence suggests, it has not been proven yet. Certainly we're not at a point where we think removing neonics would solve CCD, as the EU's experience has shown.

Update: In the years since this episode was produced, neonics have been largely let off the hook. Neonic bans in Europe produced no improvement in bee populations at all and are being relaxed. Evidence seems clear that of the pesticide options available to farmers, neonics as a class are among the least harmful to bees. —BD

The Bottom Line

When you hear it said that we don't know the cause of CCD, that doesn't mean "scientists are baffled" or that we have no clue. In fact, we know quite a lot about it. We just haven't been able to stop or reverse it yet.

When something has multiple causes, it's usually the case that those causes are interrelated in complicated ways; it's not necessarily as simple as shutting down one or two of them and the whole problem melts away. A simplified example is the ongoing mass die-off of coniferous trees in the western United States due to bark beetles. There is one cause, but it needs two legs to stand on. Bark beetles are endemic to conifers, but it is the continuing drought that causes the trees to be susceptible. Without the drought, the trees fight off the beetles. Without the beetles, the trees could weather the drought. But put them both together, and they form a threat that the trees cannot defend against. This is probably thematically similar to what the bees are going through.

We humans may or may not be able to do whatever we can do about one or more causes of CCD that we're responsible for, but whether nature does her share is a question that will probably answer itself before we figure it out. Just keep in mind that when you hear anyone claim to know "the cause" of Colony Collapse Disorder, you have very good reason to be skeptical.

By Brian Dunning

Please contact us with any corrections or feedback.


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Cite this article:
Dunning, B. "Colony Collapse Disorder: Science and Pseudoscience." Skeptoid Podcast. Skeptoid Media, 21 Jun 2016. Web. 24 Apr 2024. <>


References & Further Reading

Ballenger, J. "Are Neonicotinoids the Sole Factor Responsible for Colony Collapse Disorder?" Biology Fortified Blog. Biology Fortified, Inc., 4 Jun. 2014. Web. 8 Jun. 2016. <>

Carson, R. Silent Spring. New York: Fawcett Crest, 1964.

CCD Steering Committee. Colony Collapse Disorder and Honey Bee Health Action Plan. Washington DC: United States Department of Agriculture, 2015.

Cressey, D. "Reports spark row over bee-bothering insecticides." Nature Publishing Group, 16 Jan. 2013. Web. 9 Jun. 2016. <>

Editors. "Colony collapse disorder." RationalWiki. RationalMedia Foundation, 11 Mar. 2016. Web. 8 Jun. 2016. <>

Maini, S., Medrzycki, P., Porrini, C. "The puzzle of honey bee losses: a brief review." Bulletin of Insectology. 1 Jan. 2010, Volume 63, Number 1: 153-160.

Novella, S. "Neonicotinoids, GMOs, and Colony Collapse Disorder." Neurologica Blog. New England Skeptical Society, 30 Apr. 2015. Web. 8 Jun. 2016. <>

Porterfield, A. "Why neonicotinoid pesticides don’t deserve a ‘deadly to bees’ label." Genetic Literacy Project. Genetic Literacy Project, 15 Feb. 2019. Web. 21 May. 2019. <>

USDA. "ARS Honey Bee Health and Colony Collapse Disorder." Agricultural Research Service. United States Department of Agriculture, 10 May 2016. Web. 9 Jun. 2016. <>


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