Colony Collapse Disorder: A clue

I last wrote about Colony Collapse Disorder back in May. That’s when I made the case that CCD would not squeeze honey supplies too much and cause a large price run up. With honey prices up about 10% since then, I think my analysis was about right. I’m still anxious to learn about the impact on colonies this year, but I haven’t seen any good data on that. In fact, I hadn’t seen much in the way of new information at all until a few days ago.

Israeli Acute Paralysis Virus linked Colony Collapse Disorder

The Columbia University Mailman School of Public Health announced a study linking CCD to Israeli Acute Paralysis Virus. I haven’t found a link to the study itself, which is published in the journal Science, but ScienceDaily has published a summary. The authors of the study claim that the presence of IAPV predicts CCD in a colony with 96% accuracy. In other words, if someone selected a honey bee colony in the US and all they told you about it was whether or not it had IAPV, not how big it was, where it was, what kinds of bees they were, you could tell them if it had collapsed or not. If you did this 1000 times and had average luck, you’d be right 960 times.

But we don’t know if it actually causes CCD

That kind of accuracy is pretty amazing and makes IAPV a “significant marker” for CCD, but it doesn’t mean that it causes CCD. It might even be the other way around; CCD weakens a colony that was otherwise able to fend off IAPV, allowing the virus to infect the colony. Or something else causes both CCD and facilitates an IAPV infection.

Did IAPV come from Australia?

The study also fingered Australia as a possible source of IAPV because they found IAPV in Australian honeybees and live bee imports from Australia began close to the time that beekeepers started reporting CCD. It’s possible, but this strikes me as the weakest part of the study, and not just because we don’t really know if IAPV causes CCD. Finding IAPV in Australian bees isn’t the same thing as establishing that Australia was the source. Do we know for sure that the US was free of IAPV? Was Australia the only source of live bee imports that might have carried IAPV? To my knowledge, no and no.

Where do we go from here?

The next step for these researchers is to try and cause CCD. They’ll do this by introducing IAPV, by itself and in combination with other things that stress honeybees, into healthy colonies. The thinking is that if IAPV is the culprit, it’s not acting alone. One possible accomplice is the varroa mite, which already plagues honeybees. It’s known to suppress bees’ immune systems, so it could pave the way for IAPV to do it’s dirty work. If they can reliably cause CCD in this way, then IAPV could graduate from “significant marker” to “cause”. If not, well science has a lot more red herrings and blind alleys than it has breakthroughs. So we take what we learn from this, add it to what we already know, and keep moving forward.

Update 3/9/08: Beekeepers have staying power

The USDA’s 2007 honey report indicates that the number of producing honeybee colonies rose in 2007 by 2%. This is encouraging news and shows that beekeepers have been able to make up their losses from CCD for the second year in a row. Read more here.

Update 3/9/2009: Honeybees hang in there for another year

The 2008 Honey Report indicated that managed colonies in the US fell by only 6%. Honey production and per colony yield rose. It’s looking more and more like Colony Collapse Disorder is not a catastrophe.

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2 thoughts on “Colony Collapse Disorder: A clue

  1. Michael

    IAPV is not the cause of CCD. IT has totally different symptoms and takes months or longer to develop. CCD can wipe out a colony in 24 hours. In addition the study was of a measly 32 hives. 1 healthy hive got CCD from the control and 8 from the unhealthy. Thats where the 96% came from and so it’s not enough to say why 800,000 colonies died, many of which did not have IAPV. Plus IAPV is in hives that don’t suffer from CCD.

    It’s actually an insecticide called imidacloprid or IMD that is killing the bees, the French proved this in a 108 page report. 1.5 ppb of IMD causes CCD.

  2. Erroll Post author

    The Columbia University study identified Israeli Acute Paralysis Virus as a “significant marker,” but did not claim it caused Colony Collapse Disorder on it’s own. It might work in combination with other stressors to cause CCD, though, and that’s what they’re investigating now.

    It’s a little vague, Michael, to say “the French proved” that Imidacloprid caused CCD. How was this proven? Who, exactly, proved it? Is this 108 page report that you mention available online? Wikipedia’s article on Imidacloprid suggests that the link to French honeybee losses of the late ’90s and early 2000’s is far from proven. I’m not even sure that those losses are CCD.

    So I think the jury is still out on what’s causing CCD, but the IAPV clue is important and should be followed up. In the meantime, remember that bee die offs, with virtually identical symptoms to CCD, have occurred many times before. We never discovered the cause of those episodes, which went by names like “fall dwindle” or “disappearing disease,” but the cases go back as far as 100 years. That, of course, is long before Imidacloprid and most other modern pesticides were invented.

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