Guest Post: Honey bees, CCD, and the Elephant in the Room


Photo of Doug at workDr. Doug Yanega is the Senior Museum Scientist at the University of California, Riverside, and an acting Commissioner of the International Commission on Zoological Nomenclature. His undergraduate and graduate degrees were under the tutelage of George Eickwort (Cornell University) and Charles D. Michener (University of Kansas), respectively, two of the world’s foremost bee authorities. Dr. Yanega has a broad background, and many of his publications deal with the natural history, pollination ecology, and taxonomy of bees.  

Doug published this on Facebook, and I wanted this to get a broader audience, so invited him here for a guest post.

Back in 2006, a team of bee researchers put out a report regarding a phenomenon affecting honey bees commonly called “Fall Dwindle Disease”, in which they decided that this name was misleading, and suggested a new name for this syndrome – the name they suggested as a replacement was “Colony Collapse Disorder” (CCD). It’s worth reading it (at, not only to get some perspective on things, but because – amazingly enough – even though this is the document that first used and defined the term, virtually no one who has published on CCD has ever cited this document… not even the people who wrote it.

To anyone acquainted with scientific research or journalism, the idea of using a term that was recently defined and NOT citing (or at least reading) the original definition goes completely against what anyone would consider to be proper research. Basically, not doing one’s homework.  Yet, this is precisely what has happened with this document. It can’t even be retrieved from the website on which it originally appeared, but if you’ve read it, you’re now better educated on the history of CCD than many of the scientists and journalists and beekeepers who have published on CCD in the past 7 years.

Why do I stress this so much? It’s quite straightforward: most of the scientists and journalists and beekeepers who have published on CCD in the past 7 years have either stated or implied that CCD is something that had never existed prior to 2006. And yet, the original paper defining CCD spelled out that it was an existing condition that they were simply coining a new name for, in the hope that the new name would be less misleading. Oh, the irony. Even more baffling is that it’s not like this information was totally lost or hidden – it’s been visible in the Wikipedia article (, with a citation, for all this time, so anyone in the world who simply Googled “Colony Collapse Disorder” could find this reference, since the WikiP article is the first link shown.

It gets even better: in both 2007 and 2009 another paper pointed out that there were at least 18 historical episodes of similar large-scale losses of honey bees dating back to 1869, at least several of which had symptoms similar enough that they cannot be ruled out as being the exact same ailment. Yet, how often have you seen any of the scientists and journalists and beekeepers acknowledging that any theories about the cause of CCD need to accommodate the evidence for similar bee crashes that pre-date neonicotinoid pesticides, high-fructose corn syrup (HFCS), migratory beekeeping, cell phones, genetically modified crops, or any of the other human-made “causes” that have been run up the proverbial flagpole?

Once again, there are an awful lot of people who are not doing their homework (admittedly, it is a big body of literature, but we’re talking about papers *central* to the issue). That 2009 paper also included the following statement, and I’ll quote it because it’s so important:

“Of the more than 200 variables we quantified in this study, 61 were found with enough frequency to permit meaningful comparisons between populations. None of these measures on its own could distinguish CCD from control colonies.”

Of the 61 variables quantified (including adult bee physiology, pathogen loads, and pesticide levels), no single factor was found with enough consistency to suggest one causal agent. Bees in CCD colonies had higher pathogen loads and were co-infected with more pathogens than control populations, suggesting either greater pathogen exposure or reduced defenses in CCD bees.” Yes, this study did actually look for connections to pesticides, Varroa mites, beekeeping practices, and other things, and no such connections held up to scientific scrutiny.

Here’s the thing about this: if you look at a lot of what you see these days, be it in the scientific literature or in the media, people are running around looking for things that kill honey bees, and when they find something that does so, they often make this GARGANTUAN leap to claim that since X kills honey bees, and since CCD kills honey bees, then X must cause CCD. Logic fail, anyone?

Does anyone seriously dispute that neonicotinoid pesticides are capable of killing honey bees? No. Does anyone dispute that Varroa mites can kill honey bees? No. Does anyone dispute that Nosema (a microsporidian fungus) kills honey bees? No. Sure, there are some ridiculous claims that no one in the scientific community WOULD stand behind (e.g., cell phones or chemtrails), but, by and large, most of the things that any one team of researchers or another puts forward as THE cause of CCD are things that, in and of themselves, are perfectly plausible as significant sources of bee mortality. But that DOES NOT mean that any of them is causally linked to CCD.

beesWhy not? Go back and read the papers I linked; (1) there’s a list of symptoms that characterize CCD, which are not universally present in these various “smoking gun” studies, and (2) they’re talking about something dating back to the 1800s. Did they have neonicotinoids or HFCS back in 1869? In 1969? If not, then those studies fail to do what ANY genuinely scientific hypothesis needs to do: offer an explanation consistent with ALL of the evidence (Occam’s Razor, anyone?).

In effect, what is happening is that researchers are studying one possible factor at a time, and seeing only a tiny part of the whole picture. It’s the parable of “The Blind Men and the Elephant”, where each one describes only that which is in their range of perception, instead of examining ALL of the evidence (including reading ALL of the literature) and coming up with a theory which explains all of it. We’ve got a pile of incomplete theories all competing for the media spotlight, each with its own proponents, and sometimes with a non-scientific agenda.

They’re using a single name, CCD, but may be using it to describe a pile of entirely different ailments. Even worse, there are fringe theories and fuzzy thinking and red herrings abounding, and the public can get easily confused – for example, not realizing that there are some 20,000 species of bees in the world, and only ONE of them is affected by CCD (yes, some other species of bees are dying off, but it’s a different set of things that are responsible).

What may well be a complete and sensible theory is out there, however, and it is referred to above, and hinted at elsewhere (mostly by folks who were involved with the original CCD work) though it has not yet been fully explored or elucidated to everyone’s satisfaction; I’ll highlight again the phrase “reduced defenses in CCD bees.” Way back when this whole thing came to everyone’s attention, Diana Cox-Foster and the other researchers made observations suggesting that CCD might be the result of bees with a compromised immune system.

For those of us who remember when AIDS first came to public attention, there are some striking parallels, and it wouldn’t be all that surprising to ultimately find out that CCD is something that works in much the same way. That is, if you have bees with a compromised immune system, then they could become vulnerable in such a way that a whole range of things that normally might NOT be lethal, are suddenly lethal.

Honey bees are exposed to all sorts of pathogens, chemicals (including not just pesticides, but HFCS, and mite-killing agents used by beekeepers), and other stress-inducing factors on a routine basis, and the levels of exposure to these factors are normally not enough to kill off healthy colonies. But if they are NOT actually healthy, and instead are immuno-compromised, then those same levels of exposure might trigger something catastrophic. Recall that the HIV virus does not itself kill people; the causes of death in AIDS victims are a variety of other diseases that would ordinarily have been fought off by the immune system. If no one had ever discovered the HIV virus, we would be seeing evidence of people dying from all sorts of other things, and likely pointing blame at each factor independently, while missing that there was something connecting them all.

Sound familiar? There is (and has been, all along) evidence that CCD is contagious, yet how often is that discussed? That evidence needs to be accounted for, along with all of the other patterns we’re seeing. There are people looking for viruses and other pathogens that could be at the root of CCD, and some tantalizing results have appeared – though such announcements haven’t been definitive, and (perhaps more importantly) haven’t gotten more attention than the incomplete (but more sensational) theories have gotten.

Not only would it be nice if more of the people who reviewed papers trying to link various things to CCD asked pointed questions like “How well can this theory explain similar bee dieoffs in the previous century?” or “How well can this theory explain the patterns of contagious pathology seen in CCD-affected apiaries?”, but it would also be far more professional and appropriate to do so, given that the scientific method is not based on cherry-picking of evidence, or sensationalism. I’m prepared to find out that I’m wrong, but I want to see some real evidence, for which there is an unambiguous and coherent explanation.

A reasonable question you could ask is “Well, even if we accept the idea that there’s an underlying pathogen, why is this all happening now, and to this degree, and over this length of time? If this is the same disease we’ve seen outbreaks of spanning several decades, why does this seem so much worse this time around?” I can offer two observations: (1) the way the modern news media network seeks out and reports on stories is VERY different, as is the level of environmental concern among the general public, and even if the exact same thing DID happen in the 1960s, it would not have made international news headlines; and (2) there are, quite simply, MORE potentially harmful things that honey bees are exposed to now than they were in the past – meaning that if the diefoffs are more widespread, more severe, and more prolonged, it should not be all that surprising.

A reasonable course of action, to my mind, is acknowledging that we aren’t likely to find that any man-made factors are the true cause of CCD, devoting energy to looking for contagious pathogenic agents, and taking a closer look at genetic diversity in honey bees themselves (e.g., are there strains that are resistant to CCD?), while at the same time working towards reducing the exposure and impacts of man-made factors that are capable of harming bees (but without BLAMING them in the process, or overreacting). Does every potentially harmful thing need to be banned outright, or just used more prudently? Is there a level of exposure to neonicotinoids that is not harmful? Can beekeepers simply use less HFCS, or less or different acaricides, or make other changes to their practices that will result in fewer bee deaths? Answers may not be simple, nor black-and-white, but real science rarely is.

bees[P.S. from Doug - the day after I first posted this on Facebook, the USDA released this PDF, in which the pre-2006 existence of CCD is once again not mentioned, despite having nearly all of the original co-authors among the 175 conference attendees. This is remarkable, and makes me wonder if people are intentionally trying to distance themselves from the original definition of CCD. It’s almost like someone publishing a paper coining the term “lung cancer” and then other people coming along and using that same term for every other known form of cancer, to the point where the original concept has been forgotten entirely.

The report states explicitly that honey bees are suffering from multiple different things, which I can’t dispute, and “CCD” is (at this point) being used as a blanket term for things that may have genuinely separate causes – but this is a practice I don’t like. If we KNOW there are multiple causes and multiple effects, then it confuses the issue to lump them all under a single name, and you’re going to have serious problems coming to solid conclusions about treatment, prevention, and epidemiology, not to mention communicating with the public. I’ll give just one example to make my point: several studies show that parasitic Varroa mites are strongly linked to CCD, and several other perfectly valid studies show that CCD can kill bees that have no Varroa mites. The net effect is that all we can say is “Beekeepers should prevent their bees from getting Varroa mites” – which is something everyone has known for decades. But if it turns out that some of the chemicals used to kill Varroa mites also weaken the bees, then by failing to tease apart the different contributing factors, we’ve made a vague recommendation that might have negative consequences. I’m not saying teasing these things apart is easy – experimental research on honey bee pathology is incredibly difficult, because it’s nearly impossible to get large numbers of replicates, or establish proper controls for all variables – but I still think that we should TRY to keep the different causes separate, and maybe we can some day figure out what the original CCD was.

Other things you might want to read about pesticides and bees:

Bees and Pesticides (again)


(Latest in my series of bee posts for Scientopia)

The same day that I published my piece about bees and pesticides, the Pesticide Action Network released a report titled Honey Bees and Pesticides: State of the ScienceIt’s basically an annotated bibliography of some of the major papers over the last 9 years.

Their introduction was… well:

“Two increasingly intractable sides have emerged in this controversy:
beekeepers and environmental health advocates vs. pesticide companies and the scientists supported by them.”

That Us vs. Them language is really disturbing.  I happen to be a scientist, and a beekeeper, and an environmental health advocate. I don’t always agree with everything PAN does, but I agree much more than I disagree.  (It’s also a little odd that they would begin with this sort of divisive language, and then….turn to the products of scientists to prove their point.)

It didn’t take long before I was accused of being a “pesticide shill” after my last post cautioning that neonicotinoids are not the sole cause of colony collapse disorder.  Trust me, I am sooooo not raking in the big chemical daddy bucks.

shades of grey kitten

I’ve never said that pesticides are safe, or that they don’t harm bees–just that the story is complex.

Nuance: I Haz It.  

Personally? I think the biggest threats to honey bees are a combination of many factors–and to focus on one exclusively will not help us solve the problem. I WISH that the issue really was just the neonicotinoid class of pesticides, because that would give us an easy “off” switch for the problem.  Ban the pesticides, bees come back.  Solved.

But even if we did ban these pesticides–and deal with the giant economic upheaval in agriculture that would accompany that, BTW–honey bees aren’t going to recover, because they still are besieged by mites, and viruses, and fungal disease, and the pesticides we apply to the bees directly to control those problems. That also doesn’t begin to cover the issues with bee nutrition and forage diversity.

There is clearly a pesticide problem with bees–even if we can’t fully quantify it right now. I want to steer you away from the PAN report to another, less well known and excellent summary of this class of pesticides on bees.  The Xerces Society white paper, A Review of Research into the Effects of Neonicotinoid Insecticides on Bees, with Recommendations for Action, had this to say about CCD:

“There is no direct link demonstrated between neonicotinoids and the honeybee bee syndrome known as Colony Collapse Disorder. However, recent research suggests that nenonicotinoids may make honey bees more susceptible to parasites and pathogens….which has been implicated as one causitive factor for CCD.”

The Xerces paper is probably the best review of the recent research that you are going to find.  Not only is it written by Xerces scientists, who are folks what really know their bees, it also was reviewed by several other bee researchers I have a great deal of respect for.

Xerces thoroughly documents what we know about these pesticides and bees–and, unfortunately, we don’t know nearly enough. Most of the published research focuses on honey bees, rather than the native bee species in the US.  (Honey bees are an introduced species in North America).  That means we don’t have much data to work with to figure out how different bee species will be affected.  When you look at this chart of pesticide effects on native bees…we have no freakin’ clue how they are affected.

Personally, I found the most disturbing piece of the Xerces report to be their discovery of how many of these neonicotinoid insecticides are available over the counter to homeowners.  Calculating pesticide application rates is one of the toughest parts of farming (or pesticide applicator exams), and Xerces does the math to uncover some startling facts:

  • “Products approved for homeowners to use in gardens, lawns, and on ornamental trees have manufacturer-recommended application rates up to 120 times higher than rates approved for agricultural crops. 
  • Many neonicotinoid pesticides that are sold to homeowners for use on lawns and gardens do not have any mention of the risks of these products to bees, and the label guidance for products used in agriculture is not always clear or consistent.
  • Neonicotinoids can persist in soil for months or years after a single application. Measurable amounts of residues were found in woody plants up to six years after application.”

That is really scary.

Xerces raises some very important questions about what this means for our native bees that are already struggling with habitat loss and a spill-over of parasites and pathogens from introduced bee species. Butterflies, beetles, and flies also drink nectar and feed on pollen–pretty much any of our pollinators, including hummingbirds, could be affected if they feed on trees and plants treated with these insecticides.

I would like to see new labeling so consumers know that these products have the potential to kill bees and other pollinators, as well as a review of application rates for over-the-counter formulations.

bee photo

Unfortunately, because neonicotinoid pesticides are so very useful in agriculture, there are no easy answers. The things that make these compounds so very well suited for so many purposes–their ability to remain stable for a long time and spread through plant tissues–are also why they pose dangers for pollinating insects.

But we have to look at the whole picture to figure out how to make things right for bees.

Additional Reading: 

(Thanks to Artologica for the LOLcats!)