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Sick Bees – Part 18B: Colony Collapse Revisited




The “Harvard” Study

A Healthy Skepticism

Reality Check

A Critical Analysis

A Clarification of Terms

Can You Trust Your Spin Doctor?

Some Helpful Advice

Some Examples of Spin Doctor Malpractice

Example 1 – GMOs as the Cause of CCD

Inductive vs. Deductive Reasoning

Example 2 – Windmills as the Cause of CCD

Some More Terms

Koch’s Postulates

Circumstantial Evidence Due To “Association”

Occam’s Razor

Back to the Neonic Circus

Evaluating the Primary Suspects

Further Reading (free downloads)

References

Randy Oliver
ScientificBeekeeping.com

For immediate release: Thursday, April 5, 2012
Boston, MA – The likely culprit in sharp worldwide declines in honeybee colonies since 2006 is imidacloprid, one of the most widely used pesticides, according to a new study from Harvard School of Public Health.

The “Harvard” Study

For the past month (I’m writing these words in April) it’s been one danged headline after another claiming that the “culprit” for Colony Collapse Disorder has finally been convicted.  The recent press release above was quickly juiced up by reporters eager to make the alleged wrongdoer sound even more sinister:

“US study says nerve agent causes Colony Collapse Disorder” [1]

“Nerve agent”?  The reporter is gratuitously pandering to public fear!  Imidacloprid was developed as a “reduced risk” product to replace the nasty organophosphate insecticides (parathion, chlorpyrifos, coumaphos), which were indeed derived from deadly nerve gas.  But let’s not let facts ruin a good story…

I and many others have been publicly critical of the Harvard study.  Tellingly, the authors acknowledge that their paper was rejected when submitted to American scientific journals.   Meaningful criticism of scientific studies is the norm—scientists, in their search for the truth, are often each other’s most serious critics. This is an important point—in this case it is not necessarily the actual experiment that is being criticized; rather the controversy is about the conclusions and overreaching claims made by the authors.  Indeed, in my evaluation, rather than damning imidacloprid, the results of the trial actually appeared to demonstrate a lack of adverse effects from feeding that insecticide to colonies of bees, and certainly did not create the accepted symptoms of CCD!

I’m not going to belabor the criticism of the study here–by the time you read this article, I’m sure that the paper will be thoroughly dissected for your inspection at ScientificBeekeeping.com.

A Healthy Skepticism

If you believe everything you read, better not read–   Japanese Proverb.

Colony Collapse Disorder has been a field day for the alarmists in our society.  In their apocalyptic view, our poor bees are functioning as the canary in the coal mine, indicating that the End of the World as We Know It is imminent.  Now don’t get me wrong!  I’ve got 20/20 vision looking forward, and can see that there are serious environmental problems created by the seven billion resource-hungry human beings inhabiting the fragile skin of this finite planet.  But age has tempered my uncritical swallowing of every “The Sky is Falling” claim. 

I’m fully aware that there are legitimate problems and concerns with bees, pesticides, transgenic organisms, and corporate agriculture.  But we are best served if the debate is logical and buttressed by evidence, as opposed to being based upon irrational fears, misinformation, and fallacious arguments.

Fear is a commodity.  Lots of folk have a vested interest in selling it to the public, or to distract us from something else.  The media know that sensationalism sells!  Fiction is often more interesting than fact.  Unfortunately the press is not interested in boring details—“soundbite science” and fear mongering make the headlines; critical analysis gets buried on Page 11, if it makes the paper at all.

More to the point, special interests add their own spin in order to garner support, solicit donations, or to push a legislative or regulatory agenda.  CCD has been a poster child for all the above. 

Like the Blind Men and the Elephant, CCD could appear to be something different to everyone, depending upon how your glasses are tinted.  And if you’re a researcher, you can dang well bet that your particular field of expertise deserves funding in order to help solve the mystery, and that if you mention CCD in the press release, that you will get media attention!

Reality Check

Allow me to quote from an excellent review by Dutch bee researcher Tjeerd Blacquière [2]:

“In recent years the public in Europe and the USA has been overrun with stories about vanishing bees and with the curse in the quote attributed to Einstein: when the bee disappears, mankind will not survive for more than a few years… What is true about these stories, and how severe are the effects?  Yes, there are serious problems.  Yes, bees are very important for nature and man.  Yes, we need to act.  But where to start?  What is causing the troubles?”

“From the recent public fuss about the honeybee colony losses in Europe and North America’s ‘colony collapse disorder’ the impression arises that the world population of honeybee colonies is rapidly declining.  Be it true for those regions, it is far from true worldwide.  Based on FAO statistics …the world honeybee stock… has steadily increased.”

[What have changed are the sorts of colony morbidity and mortality being observed]:

“Traditionally, losses of colonies only became apparent in spring, when after winter beekeepers visited their hives for the first spring check…in recent years more colonies seem to be lost during winter…and autumn….In the USA the rapid population loss of colonies, especially in autumn, has been named ‘colony collapse disorder’ (CCD). This rapid dwindling of entire bee colonies very much appealed to the imagination of the public, as if the bees had gone to find a better world.”

It seems pretty clear that beekeepers are routinely experiencing annual colony loss rates above historical norms, although history is filled with episodic events of high mortality.  A winter loss rate of 5-10% was the old standard.  Losses in the U.S. over the past few years have averaged about 30%.  Some would have us believe that colony losses in Europe are also universally at unacceptably high levels; in reality though, they have been highly variable from year to year, and from country to country, with no clear pattern [3].

An appropriate quotation: “Mankind have a great aversion to intellectual labor; but even supposing knowledge to be easily attainable, more people would be content to be ignorant than would take even a little trouble to acquire it” –Samuel Johnson (1709-1784)

There are excellent reviews of the actual situation, freely available on the internet.  I suggest that any beekeeper interested in knowing the true facts read them (I put some recommended reviews in References).

A Critical Analysis

So perhaps now would be a good time to cut through the spin, the suppositions, and the unsubstantiated claims about the causes for CCD.  Heck, I goaded the “Beekeeper Taliban,” so why not ruffle some more feathers?  But before we start butchering sacred cows, let’s agree on some terminology:

A Clarification of Terms

  • Colony morbidity or “weakening” relates to the incidence of unhealthiness.  One might notice slower colony build up, poor brood patterns, decreased honey production, increased queen supersedure or failure, small populations in fall, or poor wintering.
  • Colony mortality is a generic term for any colony losses—which often, but not necessarily, happen during the fall and winter.  Starvation, queen failure, tracheal mite, AFB, outright pesticide poisoning, and weakness of colonies in fall are typical causes.
  • Colony depopulation is the dwindling to nothing of the colony population over time, a result of the attrition of adult bees exceeding recruitment from the rearing of additional brood.  This process can happen slowly or quickly.  Known causes are high levels of varroa, viruses, or nosema; or winter losses associated with poor nutrition or late-season exposure to some pesticides.
  •  Colony Collapse defines a specific (depending upon the author) set of “symptoms”—namely the seemingly sudden disappearance of the adult population of the hive, plus the distinctive characteristic of leaving brood behind (which differentiates it from “normal” collapse due to varroa).  Additionally, in some cases, there appears to also be a lack of hive scavengers in the abandoned hives.
  • The causative agent of a disease is the pathogen, toxin, or other factor responsible for the observed signs of illness.

It’s important to keep the differences between the above terms straight, since they are often loosely thrown about to inappropriately support one point of view or another.

Can you trust your spin doctor?

When I first heard that European beekeepers were protesting that a new insecticide (Gaucho) was killing off their bees, memories of Rachel Carson, DDT, and the plight of the raptors came flooding back.  My gut reaction was, here we go again—technology has created a new monster!  It made for a great story: evil German pesticide manufacturer destroying the environment,  poor innocent bees suffering from it, and beleaguered French beekeepers bravely waging a David vs. Goliath battle (of course a few movies were soon produced following these popular storylines).

In recent years, the public’s confidence in authority has been shaken, and today distrust of Big Government, Big Corporations, and Big Money runs rampant.  The Internet now gives Joe Public access to more information than any single person can possibly digest.  So we depend upon “experts” to think for us.

Unfortunately, the Internet also has spelled the demise of good editorship and well-researched investigative journalism.  It has also given new life to the quote that “A lie can travel halfway round the world while the truth is still putting on its shoes” (this quote is generally misattributed to Mark Twain).  What happens is that unsubstantiated claims resonate with the public, go viral, and become urban legends.  Most folk simply aren’t willing to do the homework necessary to sort fact from fiction.

So one must be careful to ask whether they can trust their favorite “spin doctors.”  It is ever so easy to fall into the trap of “confirmation bias.”

Confirmation Bias

“For what a man more likes to be true, he more readily believes”–Francis Bacon (1561-1626)

It is human nature that once you’ve formed an opinion on something, that you tend to only pay attention to supportive evidence, and to gloss over anything to the contrary.  I find myself as guilty of this as any.  For example, once I reached the opinion that Nosema ceranae was not a major problem, it was all too easy to find studies and field observations that supported my biased point of view; and conversely, to find fault with any reports that suggested that that parasite was actually harmful.

On the other hand, there is no greater delight for me than to prove myself wrong on something!  I force myself to continually question any and all of my personal opinions and biases.  Plus I feel that I owe it to my ever-trusting readers to report objectively and truthfully.  So I continued to observe, experiment, and examine data that was contrary to my opinion, which eventually led me to reevaluate my assessment of Nosema ceranae! (I promise you that if indeed cell phones are eventually found to be the actual cause of CCD, I’ll be the first to let you know…)

CCD is still a hot topic in the public’s eye.  Editors and bloggers know that their readers are eager to witness the public crucifixion of the pesticide manufacturers—it’s a guaranteed way to sell magazines, to get more hits on your blog, or to have your scientific paper cited.  The result is continual confirmation bias—such that the public only hears, again and again, that it is GMO’s and/or seed treatments causing CCD (most folk have these two pretty much jumbled up in their minds as a single evil entity).

In reality, there is a great body of scientific research that is simply deemed too “boring” to make the popular press, and therefore the public seldom hears what the majority of the bee research community feels are the most likely causes of colony mortality.  But by all means, don’t take my word for anything—I recommend that you research the facts yourself!  The papers and web pages in References would be a good start.

Some helpful advice

In my lifetime, I’ve been told to live in fear of commies, DDT, fluoride in the water, red dye #2, animal fat, the mercury in my fillings, and Saddam’s weapons of mass destruction.  As it turns out, those fears were all unfounded and overblown.

Today the internet has helped to boost the level of fear in the populace to an all-time high.  The current hobgoblins—vaccinations, chemtrails, liberals, GMO’s, cell phone radiation, high fructose corn syrup,  and neonicotinoid insecticides—have people trembling in their shoes.  This is surprising, given that we are actually living in the safest period in human history, water and air pollution have been largely cleaned up, life expectancy is longer than ever, and today’s pesticides are much safer than the older generations of chemicals!

Yet, impassioned activists still find a receptive audience when they play to fear about the imagined demise of the honey bee.   They demonize their alleged villains, often twisting the facts to fit their beliefs.  You may find in their writings:

  • Spurious correlations or circumstantial evidence
  • Unfettered speculation and conjecture masquerading as fact
  • Unwarranted expansion from unsubstantiated suppositions (try to say that one three times real fast!)
  • Wild extrapolations from minor bits of data

The problem is that these extremists foment unfounded fear and passion in a public that is rightfully worried about environmental issues. 

May I suggest that you take pronouncements from anyone who is vehement, adamant, or absolutely certain about anything with a grain of salt?  The more fervent, fanatical, or impassioned the speaker (I personally watch for frothing about the mouth), the less you may wish to trust their objective judgment.

Sorting opinion from fact

“The fact that an opinion has been widely held is no evidence whatever that it is not utterly absurd; indeed in view of the silliness of the majority of mankind, a widespread belief is more likely to be foolish than sensible.” –Bertrand Russell (1872-1970)

Need I say more?

Some examples of spin doctor malpractice

Example 1—GMO’s as the cause of CCD

Perhaps this will surprise you, but some zealots actually fabricate preposterous stories about their bugaboo of choice.  One anti-GMO blogger has a thoroughly convincing webpage [4] that definitively links CCD to GMO’s (the battle of the acronyms?).  The author posted compelling full-color photomicrographs (Figure 1; what could be more convincing than pictures taken through a microscope?) of dissected bee guts that demonstrated the damage caused by the bees’ ingestion of pollen from GMO crops.

Figure 1. This photo was offered as definitive proof that GMOs were the cause of CCD! In actuality, the photo had been reproduced, with the caption altered, from the original study on CCD by Dennis vanEngelsorp [11], in which neither the words “GMO” nor “digestive shutdown” were ever mentioned! Photo reprinted here by permission.

The anti-GMO author’s “research” sounds very scientific.  He concludes that: 

 “The proof is obvious that one of the major reasons of the bees’ decline is by the ingestion of GMO proteins.  As seen above, it is certain that the digestive shutdown is due to hard material in the digestive tract that compromises the immune system. Circulatory problems would without doubt [sic]. Could it be that humans are going through the same process with the rise of Colon Cancer? As seen below in the comparison of the healthy bee and the unhealthy bee, it is obvious that the bees that are ingesting GMO pollen are having severe digestive problems, so severe that the disease is terminal.”

The problem is that the author was so obsessed with proving that GMO’s caused CCD that he started just making things up (there is no “hard material” in Bt corn; nor does hard material in the digestive track compromise the immune system)!

What the author of the above webpage is guilty of is “deductive reasoning”—conclusions that were “obvious” to him might have been less obvious to a more objective observer.

Example of deductive reasoning:  I observe unusual death of my colonies. My favorite bogeyman (cell phones, GMO’s, some pesticide) surely kills bees.  Therefore, that bogeyman must be the culprit!  Deductive reasoning is the basis of faith-based reasoning—the faith comes first, and then you search for any sort of evidence that might possibly be construed to lend support to that belief.

I can almost guarantee that any experimental results from some labs will be interpreted to support the premise that the neonics are the root cause of colony collapse (they’ve already got their minds made up).  Other scientists, tongue in cheek, refer to this practice as “painting the bulls eye around the arrow.”  Some of the recent papers purporting to have found a “link” between systemic insecticides and CCD certainly fall into this category.

On the other hand:

Example of inductive reasoning:  I observe unusual death of my colonies.  I will objectively look for any clues as to what may be killing them, come up with some testable hypotheses, and then perform experiments to determine which explanations hold up to scrutiny (in other words, the Scientific Method).

Dr. Dennis vanEngelsdorp, Dr. Jeff Pettis, the staffs at the Beltsville Bee Lab and Penn State University on the East Coast, and Dr. Jerry Bromenshenk in the West, have been diligently and objectively searching for the causal factors of CCD.  I applaud these hardworking researchers for their Herculean efforts!

I suggest to the reader, that if your your favorite spin doctor is using deductive (mind already made up) reasoning, that you take his prescription with a healthy dose of skepticism!

Other extremists conjure up “linkages” or “association” between their boogeyman and CCD:

Example 2—Windmills as the cause of CCD

Headline: “Wind Farms May Be Responsible For Mass Honeybee Disappearance” [5].

“The drastic increase in the number of wind farms in the United States began between 2004 and 2005, and has blossomed to cover vast sections of the country today, as seen on the blue map below” (Figure 2;  I had to substitute a similar map in green due to copyright restrictions; the orange map was created by Dr. Jerry Bromenshenk).

“Interesting to note is the time frame of drastic increases of the number of wind farms from 2004 to 2005…This time frame becomes very important, because it is also the exact time when massive disappearances of honey bees began to be reported, beginning in 2005, with drastic increases in the years to follow. …the direct link to wind farms for the massive die off can be made.”

Figure 2.  A compelling case for the clear “direct link” between wind farms and incidence of CCD! 

The question is, is the apparent association between windmills and CCD causal, or merely coincidental?

Some More Terms

Koch’s Postulates

When tasked with the challenge of identifying the proximate cause of a disease (such as colony collapse), medical investigators follow a logic laid out by Dr. Robert Koch (rhymes with “Coke”) in 1884, who nailed the pathogens responsible for anthrax and tuberculosis.  In his day, people would superstitiously blame disease upon a wild diversity of suspects.  Dr. Koch postulated a series of logical tests to apply to any suspected cause of a specific disease.

Koch’s Postulates (which I’ve here greatly generalized, shortened, and simplified):

1.  Is the suspect factor always associated with the disease?
 
2.  Will the suspect factor always create the same symptoms?

In other words, if something is causing CCD, then you should (1) always find it present when colonies collapse; and (2) you should be able to experimentally induce CCD by introducing or applying that factor to healthy colonies. 

So let’s apply to Koch’s Postulates to windmills and CCD:

1.  Are windmills always present when CCD occurs?  I asked some CCD investigators; the answer was no!

2.  Can you create CCD in healthy colonies by placing them near windmills?  Again no, since many apiaries thrive in the presence of wind towers.  So, the windmill/CCD “direct link” does not pass the test of Koch’s Postulates.

Important note:  the second postulate is the one in which I place my greatest faith—if some factor is truly the cause of CCD, then you should be able to isolate it and then experimentally introduce or apply it to healthy colonies, and create CCD under controlled conditions.  I will present examples of experimentally-induced colony collapse later in this series.

Circumstantial evidence due to “association”

It is easy to dream up spurious correlations such as the one above—scientists are always forced to sort them out.  For example, the sales of women’s swimwear at Walmart would surely correlate with the number of drowning incidents in the Midwest.  The obvious question then is whether it is plausible that the factor (swimsuit sales) actually causes the disease (drowning), rather than merely being associated with it.   I’m not hearing of any groups calling for the banning of women’s swimwear, although I’m sure that an activist could easily solicit a million signatures for a petition to do so!

Scientists use another test when looking for explanations:

Occam’s Razor

Named after medieval monk William of Occam, it can be loosely summarized as:

The simplest explanation is usually the right one.

The application of Occam’s razor would suggest that the apparent link between swimsuit sales and drowning could be most simply explained by the fact that one is far more likely to drown if one is swimming (I’ll bet that you had already figured that one out by yourselves).  Occam’s razor helps us to avoid superstitious, convoluted, fantastic, or biologically implausible explanations.

When folk blame CCD upon an exposure to some factor that causes no observable effects at the time of exposure, but through some convoluted sequence of events  causes colonies to collapse several months (and several brood cycles) later, they are not applying Occam’s razor, which would suggest a more parsimonious explanation.

For example, the application of Occam’s razor suggests that prior to blaming any other suspect, one should first determine whether varroa levels had gotten high in those colonies during the previous summer, or whether nosema levels were high at the time of the collapse.  In other words, first eliminate the most obvious suspects (Fig. 3).

Figure 3. Before one blames colony collapse upon some exotic factor, one should first eliminate the most common causes of colony depopulation—such as high varroa levels in late summer leading to in-hive epidemics of Deformed Wing Virus (above), other viruses, or a high prevalence of nosema in the colony population.

 

A case of premature misaccusation?

Several recent headlines, and some activist groups, claim to have “linked” systemic insecticides to CCD—as in the following sentence from a letter sent to the EPA: “Clothianidin is a widely used pesticide linked to a severe and dangerous decline in pollinator populations.” 

For good measure, such a claim of linkage is generally followed by an exaggerated claim of impending doom, as from the same letter: “As we are sure you appreciate, the failure of the agency to provide adequate protection for pollinators under its pesticide registration program creates an emergency with imminent hazards: Food production, public health and the environment are all seriously threatened, and the collapse of the commercial honeybee-keeping industry would result in economic harm of the highest magnitude for U.S. agriculture.”  Wow, does Chicken Little come to mind?

I can envision the scene at the EPA when presented with the letter.  The EPA risk assessors have carefully read every bit of published research on clothianidin, and then some, and know fully well that no one has ever produced any actual evidence linking it to pollinator decline [6].  So they drop the letter into the round filing cabinet, write the beekeepers a polite response [7], and continue their accelerated comprehensive re-evaluation of these pesticides [8].

For the record, beekeepers have every right and reason to question the safely of any pesticide.  But the mere act of questioning certainly doesn’t prove that a pesticide is actually causing harm!  Not all of our beekeeper representatives wanted to send that letter to the EPA; suffice it to say that there were strong words.  Some of us want the bee industry to stick to facts and evidence!

When beekeepers make exaggerated and unsubstantiated claims, they stand the risk of damaging their credibility in the eyes of the regulatory agencies.  This is a dangerous game to play!  On one hand, it’s good to drum up public support for our beleaguered industry; but on the other hand, if we lose credibility with the regulators, they may simply dismiss us as being uniformed and irrational.  We should also keep in mind the story of The Little Boy who Cried Wolf.  What kind of audience are beekeepers going to get at EPA the next time we beg them to review another pesticide?

In reality, the EPA is very much the beekeepers’ friend—they go out of their way to make sure that pesticides are registered so as to cause the least amount of harm to honeybees [9].  I assure the reader that EPA is well aware of any and all issues and suspicions involving the neonicotinoid insecticides.  It doesn’t help our cause when we insult the Agency, and tell them how to do their job, as was done in a recent petition also signed by some beekeepers: “EPA has frankly dropped the ball… [and] should promptly suspend the registration of clothianidin and issue a stop sale” [10].

On what grounds?  I’m not saying that neonics are necessarily innocent (we’ll get to them in my next article); what I’m saying is that it is premature for beekeepers to demand a conviction without any actual evidence!  The Farm Lobby would not give up of one of their favorite insecticides without a fight (they have no love for radical environmentalists nor the EPA), and as a beekeeper, I’d rather that farmers not consider me as “the enemy.” 

The unfortunate thing about the situation is that the leadership of our bee industry has become polarized on this issue, and for merely pointing out the facts, one can get labeled as being a shill for the pesticide companies!  How absurd!  For crying out loud, the neonics were developed to be the very sort of “reduced risk” insecticides that we environmentalists had long asked for.  They are hardly perfect, but they appear to be a damn sight better than those that they replaced.

In my humble opinion, rather than using deductive reasoning and weak arguments in calling for an unlikely ban, beekeepers would be better served sticking to the facts and supporting the USDA action plan [12] for determining the cause(s) of increased colony losses.  If a link to the systemic pesticides is found, I’m confident that the EPA will act decisively!

Evaluating the Primary Suspects

The focus of this article is to put the suspects for CCD and increased colony mortality to the test.  So next month I will use the Scientific Method and apply Koch’s Postulates and Occam’s razor to each suspect cause of CCD:

  • Environmental factors
  • Chemical agents
  • Beekeeping practices
  • Biological agents

As always, I strive to be an equal opportunity offender—if there is anyone whose feathers I have not yet ruffled, I don’t want you to feel left out, so please let me know!

Further Reading (free downloads):

Examples of how the public has been misled by bad science, bad reporting, and hysteria.  Lieberman, A, et al (2004) A review of the greatest unfounded health scares of recent times.  http://www.acsh.org/docLib/20040928_fvf2004.pdf; also check their home page for more recent unfounded fears.

One of the best overall objective reports is from a European think tank called OPERA.  I highly recommend:  OPERA (2011) Bee health in Europe – Facts and Figures http://www.pollinator.org/PDFs/OPERAReport.pdf

Another excellent overall review of colony mortality in Europe is by the French Food Safety Agency: AFSSA (2009) Mortalités, effondrements et affaiblissements des colonies d’abeilles (Weakening, collapse and mortality of bee colonies).  http://www.afssa.fr/Documents/SANT-Ra-MortaliteAbeilles.pdf

COLOSS (Prevention of COlony LOSSes):  the international cooperative network investigating colony loss: http://www.coloss.org/publications

The definitive report on CCD in the U.S.: VanEngelsdorp, D, et al (2009) Colony Collapse Disorder: A Descriptive Study  http://www.plosone.org/article/info:doi/10.1371/journal.pone.0006481

A special issue of Journal of Apicultural Research focuses on colony losses.  Several good papers are open access:   http://www.ibra.org.uk/articles/JAR-SPECIAL-ISSUE-Colony-Losses

Interesting blogs by Bill Frezza “When Scientists, Lawyers, and Journalists go Viral” http://www.realclearmarkets.com/articles/2011/01/10/when_scientists_lawyers_and_journalists_go_viral_98825.html and “The Financially Driven Erosion Of Scientific Integrity” http://cei.org/op-eds-articles/financially-driven-erosion-scientific-integrity

References

[1] http://www.independent.co.uk/environment/nature/new-pesticide-link-to-sudden-decline-in-bee-population-7622263.html

[2] Blacquière, T (2010) Care for bees: for many reasons and in many ways.  Proc. Neth. Entomol. Soc. Meet. 21: 35-41. http://edepot.wur.nl/185843

[3] Maps of changing colony mortality rates by country in Europe 2002-2008: http://www.efsa.europa.eu/it/scdocs/doc/27e.pdf

[4] http://www.globalresearch.ca/index.php?context=va&aid=25950

[5] http://www.ufodigest.com/article/wind-farms-may-be-responsible-mass-honeybee-disappearance

[6] http://www.epa.gov/pesticides/about/intheworks/honeybee.htm

[7] http://www.epa.gov/pesticides/about/intheworks/clothianidin-response-letter.pdf

[8] http://www.epa.gov/pesticides/about/intheworks/clothianidin-registration-status.html

[9] http://www.epa.gov/opp00001/ecosystem/pollinator/index.html

[10] http://www.panna.org/sites/default/files/CFS-Clothianidin-Petition-3-20-12.pdf

[11] vanEngelsdorp, D, et al (2006) “Fall-Dwindle Disease”: Investigations into the causes of sudden and alarming colony losses experienced by beekeepers in the fall of 2006.  http://www.freshfromflorida.com/pi/plantinsp/apiary/fall_dwindle_report.pdf

[12] The 2007 USDA CCD Action Plan:  Any beekeeper concerned about CCD should familiarize himself with this excellent plan that details how the USDA is attempting to determine the actual cause(s) of CCD http://www.ars.usda.gov/is/br/ccd/ccd_actionplan.pdf

Updates to the above: http://www.extension.org/category/ccd

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