Why are the bees disappearing?

May 29, 2007

Dear Straight Dope:

[An update has been added to the end of this column.]

What in blazes is going on with the world's bees? I keep reading all these stories about how a significant percentage of the world's beehives are failing and that all the bees are dying. No one seems to know why, but there are explanations aplenty, ranging from global warming to mites to, of all things, cell phones! What's worse, some of these stories quote Albert Einstein's predictions that if the world's bees were ever to die off, owing to the lack of pollinators, humanity would follow about four years later. Is there anything we can do about this? If the bees all die, are there any substitute pollinators we can use? Or is Einstein right and we're all doomed?

— Rich Swank, Orlando, FL

SDSTAFF Doug replies:

Not to brag, but thanks to Wikipedia I've become the #1 authority on disappearing bees. Type "colony collapse disorder" into Google and hit return – the top hit is the Wikipedia page I maintain on the subject. (In real life I'm an entomologist with the University of California at Riverside.) Here's a summary.

First and most important: There are some 20,000 species of bees in the world, and many thousands more types of pollinating insects. What you're hearing about, "colony collapse disorder," affects one species of bee – the European honey bee. That species happens to be the one global agriculture relies upon for about 30% of its pollination requirements. So while we're not talking about losing all the world's pollinators, we are talking about losing a significant fraction of them. That's the worst-case scenario, with the species wiped out completely.

Second, there's no reason at this point to think European honey bees are going to be wiped out, now or ever. The die-offs so far appear to affect some beekeepers more than others, sometimes in the same area. That's one reason scientists are so puzzled, but it strongly suggests the losses may have something to do with how individual beekeepers are managing their bees. The "significant percentage" of failing hives is still a drop in the bucket when viewed against the global population of honey bees, and there are lots of beekeepers (even in the U.S., which appears hardest hit) who have not had, and may never have, significant losses of colonies. Plenty of honey bees remain to replace the ones that have died. It's not yet time to scream that the sky is falling.

Third, it's almost impossible to get hard numbers on how many colonies have died recently, and how much of the current uproar is media hype based on guesses, estimates and anecdotal accounts from the handful of beekeepers who have had the most colony losses. If you talk to other beekeepers, most admit they have colonies die off every winter, but they don't always keep records on how many. A lot of the reports we're hearing are based on personal recollection rather than careful documentation. In other words, the scary figures you're hearing could be exaggerated.

Fourth, even the original report describing and naming the phenomenon explicitly says it's something that has been seen before (repeatedly), named before, and studied before – in all cases without coming to any conclusion about the cause. The researchers didn't like the older names for the syndrome (which usually included the word "disease," which has connotations about infectiousness that don't seem applicable here), so they renamed it colony collapse disorder. That point has largely eluded the press, with the result that most people think this is a new phenomenon, when in fact the researchers who described it note reports of similar die-offs dating back to the 1890s.

Fifth, if what we're seeing is indeed a recurrence of a century-old phenomenon, that's a pretty good argument against theories of causation involving things that haven't been around that long. Yes, it's an assumption that current and past die-offs have a common underlying cause. Some researchers don't accept that assumption – they're the ones proposing things like pesticides as possible causes, and they may yet prove to be correct, since some modern pesticides can indeed kill honey bee colonies in a manner consistent with the present symptoms. But the leading hypothesis in many researcher's minds is that colonies are dying primarily because of stress. Stress means something different to a honey bee colony than to a human, but the basic idea isn't all that alien: If a colony is infected with a fungus, or has mites, or has pesticides in its honey, or is overheated, or is undernourished, or is losing workers due to spraying, or any other such thing, then the colony is experiencing stress. Stress in turn can cause behavioral changes that exacerbate the problem and lead to worse ones like immune system failure. Colony stress has existed, in various forms and with various causes, as long as mankind has kept honey bees, so it could indeed have happened in the 1890s. Many modern developments like pesticides or mite infestations can also cause stress (in fact, many of the things theorized to be involved can cause stress, so it's possible multiple factors are contributing to the problem, not just one). Unfortunately, stress is difficult to quantify and control experimentally, so it may never be possible to prove scientifically that colony stress explains all this year's deaths.

Sixth, it's never a good idea to trust what the media are telling you. At least once in the present case the media got something completely wrong and created a huge mess: The story about cell phones was basically a misrepresentation of what one pair of reporters wrote about a study that they misinterpreted. In a nutshell, the original research didn't involve cell phones, and the researchers never said their research was related to honey bee colony die-offs. Even details like the alleged Einstein quote are dubious. No one has yet found proof that Einstein said anything about bees dying off – the earliest documented appearance of the "quote" is 1994 and, yes, Albert was dead at the time.

The bottom line? No one is certain what's going on, but a lot of the theories can't – by themselves – explain everything we're seeing. More important, the situation hasn't yet risen to the level of a catastrophe (except, sadly, for some of the affected beekeepers). If the same thing keeps happening every winter for another decade or so, then we might really start worrying. But for now, classifying this as a "problem with potentially severe economic impact should it persist" would be a more realistic assessment.

— Doug
Straight Dope Science Advisory Board

Update (November 11, 2008)

This spring there was virtually no media discussion of European honey bees and whether or not they're disappearing. According to Diana Cox-Foster, a leading researcher on the phenomenon known as colony collapse disorder whom I met and talked with a few weeks ago, CCD hasn't gone away, but since the past winter's die-offs were not exceptionally bad, it no longer seems like the end of the world – now it's just another element among the many that contribute to overwintering mortality each year.

About the only new information out there is growing evidence that the bee disease called Israel Acute Paralysis Virus may play an important role in CCD but isn't the sole factor. An April press release (.PDF) on the CCD/IAPV relationship put out by the Mid-Atlantic Apiculture Research and Extension Consortium was remarkably low-key and noncommittal, suggesting (to me at least) that no one wants to stick his neck out on this issue or draw any more attention to it until and unless something more definitive emerges. I think the idea is to let the noise and furor over CCD die down while the experts take the time to do careful, patient research on the matter.

In short, what's happened is pretty much what I expected would happen: the CCD threat got blown out of proportion; lots of people came up with wild conjectures to explain it, none of which panned out; the dramatic phenomenon didn't repeat itself; and now people only dimly recall what all the fuss was about. I very much get the feeling that what many of us were saying about careless or incompetent beekeeping – i.e., that hive management skills had a lot to do with which beekeepers were affected – was right on the money, and the reason that the die-offs weren't as severe this year, and that the research has not been altogether revealing, is because all those incompetent beekeepers either (a) are out of business or (b) wised up when they realized that people were now paying attention to their iffy practices.

Consider the following (purely hypothetical) scenario: A beekeeper starts using a chemical to treat mites in his hives – one that isn't government approved. He could lose his certification if anyone finds out. It works better than the government-approved miticides for the first year or two, so he shares the formula with his friends, and soon a whole bunch of beekeepers are secretly doing stuff that the authorities wouldn't be OK with. But then trouble sets in: they suffer a bad drought in the fall of 2006 followed by massive problems with CCD in 2007, and suddenly a whole swarm of inspectors and researchers appears, poking around their operations, peeking in their chemical storage sheds, and asking for comb samples to run tests on. What do the beekeepers do? They destroy their bees and combs, sterilize or destroy their equipment, and dispose of anything else that could get them in trouble. So by the time anyone gets to seriously scrutinizing them, they're running a clean operation. And, lo and behold, when they go back to using the approved miticides, their die-off levels return to where they were before the beekeepers started experimenting with their new secret formula.

Now: who exactly is ever going to be able to document any of this, since no one will admit to using non-approved chemicals? How can you research and evaluate practices that no one will admit to engaging in? It's like sending uniformed Border Patrol officers out to ring the doorbell of every home in California and ask, "Are there any illegal aliens in this household?" Would you trust the resulting statistics showing that there are no illegal aliens in California? And even if a few beekeepers admit off the record to bending the rules, how can anyone pursue the matter without being accused of defamation, and faced with not just a brick wall of denial but lawsuits? One must recognize that it doesn't always take a massive cover-up effort or conspiracy to conceal the truth: sometimes the truth just can't attain escape velocity.

— Doug
Straight Dope Science Advisory Board