To bee or not to bee

When I’ve written previously about colony collapse disorder it’s generated a lot of interest, so today we have an update from regular guest blogger:

Ed Rybicki, Department of Molecular and Cell Biology, University of Cape Town, South Africa.

A major recent mystery in US agriculture has been the phenomenon of “colony collapse disorder” (CCD) in honey bees. The phenomenon, which has manifested itself all over the US in the northern hemisphere winter of 2006-2007, has caused losses of 30-90% in individual hives – with adult worker bees mysteriously missing, with no dead bees in or around the hive. This is unusual, as a good method for sampling diseases of honey bees is simply to collect the dead bees shoveled out of hives by other workers. All sorts of reasons have been advanced to explain the problem, with cumulative insecticide / pesticide / herbicide poisoning high on the list – and meanwhile the bees continue to disappear, and the concern mounts as flowers go unpollinated, and crops may fail as a result.

IAPVNow US Dept of Agriculture researchers, working with others from Pennsylvania State and Columbia Universities, have provided very strong evidence that the disorder may be due to a single infectious agent: Israeli acute paralysis virus (IAPV) of bees, which is probably a strain of Kashmir bee virus. These are dicistroviruses: these are in a superfamily related to picornaviruses, but with two open reading frames rather than one, and the three structural proteins at the 3′ rather than the 5′ end of the ss(+)RNA genome. The virus can be transmitted between bees by the varroa mite, a common pest of honey bee hives in the US and elsewhere. Their work has just been published in Science magazine (A Metagenomic Survey of Microbes in Honey Bee Colony Collapse Disorder. Science Express Reports, September 6 2007).

The approach used by the team was a “brute force” high-throughput sequencing effort, in which total nucleic acids from honey bees collected from 30 colonies with CCD and 21 colonies with no CCD from four locations in the United States were screened. The team found genomes of six symbiotic bacteria and eight bacterial groups, 81 fungi from four lineages, and seven viruses. However, the only pathogen associated with nearly all CCD samples – 96.1% – and not with healthy bees, was IAPV. While this is not proof that the virus caused the problem – the small matter of Koch’s Postulates rears its ugly head – it seems the best candidate. As to the why and how – well, there’s going to be a lot of work and (possibly funding) for some lucky virologists.

In the words of the press release from the USDA, “Pollination is a critical element in agriculture, as honey bees pollinate more than 130 crops in the United States and add $15 billion in crop value annually. There were enough honey bees to provide pollination for U.S. agriculture this year, but beekeepers could face a serious problem next year and beyond if CCD becomes more widespread and no treatment is developed.”

They could always wait for the Africanized bees to get there …

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7 Comments

  • spurius says:

    This is very interesting. But we should all admit that nobody knows what is happening to the bees.

    Please read these articles:

    http://spurius.wordpress.com/2007/09/10/befuddled-again/

    and

    http://spurius.wordpress.com/2007/09/08/honey-bees-and-cell-phones-a-go-go/

  • lstanford82 says:

    I like that we are looking at the problem due to the fact that Bee’s could be considered an indicator species and there could be a bigger ecological factor some where. I hope that we continue to worry about our little working friends.

  • Ed Rybicki says:

    You know, I would be a lot more convinced that IAPV was the sole cause if I didn’t know that viruses pop up in insects due to stress responses: we discovered 4 insect viruses in our labs because they suddenly appeared in crowded insect colonies (2 aphid viruses – one also a dicistrovirus causing paralysis – and 2 stinkbug viruses).

    So perhaps IAPV is part of the syndrome rather than the cause…? But if you could prevent our stripy little friends getting it in the first place, maybe the cell phones and insecticides / pesticides wouldn’t be sufficient to upset them.

    A lot of work waiting out there for some lucky someones.

  • lstanford82 says:

    I agree, still there are the bees that are not present. Where are they? What in the virus causes them to leave the hive and not come back? I think that it is a good start but there has to be something else. I agree withe the above post that it might be an issue but not the total cause. I think that there as to be more studies as they say above there is a lot of money that might be thrown out there.