[I have also posted this at Skepchick.]
If you read my Blog, you know that I’ve been commenting lately on Colony Collapse Disorder. CCD is the name that has been given to the latest, and what seems to be the most serious, die-off of honey bee colonies across the US and some areas of Europe.
Honeybees are domesticated animals. Like cows and chickens, they came to America with Europeans as introduced species in the 1600’s. They rapidly displaced the native bee species, and habitat loss due to agriculture and urbanization further weakened our native pollinators.
Honeybees live in artificial “barns” we build for them, and work to pollinate crops that grow in huge monocultures of single plant species. It’s an inherently artificial system. It’s also one that works really well–the value of pollination services is in the Billions yearly in the US.
The New York Times ran an excellent article earlier this week that details some of what is known:
- Honeybees in Europe and the US are dying. Fact.
- We just don’t know what the cause is, or if any single cause exists. Fact.
- We depend heavily on honeybees for pollination services for fruits, vegetables, and some animal food crops. Fact.
Unfortunately, after those statements, things get a little fuzzy. We simply don’t have enough information to say what is killing honey bees, if this is a short-term phenomena, or if the colony death reports are similar in cause.
Part of the problem is that bees tend to die on the wing. They’re off foraging for nectar, and suddenly keel over. Another name for CCD is “Vanishing Bee Syndrome”, where a bee colony will suddenly drop in numbers.
Imagine if people all over the US called up the USDA to report their cows were disappearing:
“Hello? My cows are gone.”
“Did they die? What was the cause?”
“I dunno. Some are dead. But mostly gone.”
You can imagine the potential for conspiracy theorists
Because there are few bodies for a post-mortem, this makes things difficult. In the words of a recent news release from a beekeepers conference, the colony deaths have been blamed on just about anything, including “power lines, cell phones, and Martians.” My favorite explanation is that the bees have been raptured.
The mixture of fear of catastrophic consequences and complex, murky science has lent itself to some wild claims, both in the media and online, which we should quite correctly be skeptical of. What are some of the claims?
Our old friend quantum science is trotted out in a theory that sunspots are disrupting bee communication.
In one item, the cause was blamed on “the 250 HZ signals being pumped out of GWEN (ground wave emergency network) stations all over America. This signal makes people angry, so that they support the administrations idea of going after Iran and violence in general. It works great for mass manipulation of opinion. Unfortunately, the same signal will induce a misdirection of up to 10 degrees in the navigation ability of the honeybee.”
A variation on this theory was suggested by someone who clearly doesn’t have a firm grasp on the difference between FM/AM radio and cell transmissions. (Although he might be onto something with the Steve Miller Band idea.)
Like many public misunderstandings of science, there are kernels of truth in these reports. Let’s go through the proposed causes:
EMF, cell phones, etc.
There is evidence bees can be disoriented by magnetic field bursts–under certain conditions rarely encountered. Researchers are interested in bee orientation, so sometimes experiment with ways to manipulate bees’ navigation systems.
A small preliminary paper published by a German graduate student about bees and EMF was covered heavily in the media. And, as it turns out, very incorrectly.
For example, this story in a Toronto paper starts “Martin Weatherall isn’t surprised that a German researcher has linked cellphone radiation to the mysterious disappearance of millions of bees around the globe.”
The actual research didn’t use cell phones, though. They used mobile phones, which are quite different. They were interested in bee learning in the presence of EMF in the 1880-1900 MHz range–not the 250 MHz range quoted above by alarmists. (FYI, my cell phone is in the 800MHz range, and my cordless phone is 2.4 GHz. I also refer you to this article about EMF, with a quote at the top from the head of the American Physical Society.)
The German researchers have frantically been emailing and calling around the globe, trying to disavow the link between cell phones and bees and set the story straight. This may have seriously damaged one poor scientist’s reputation, and all for a sound bite.
Genetically Modified (GM) plants
GM plants are still in the list of possible causes, but little data exists to connect colonies that have collapsed to these plants. A paper published last month by the CCD Working Group concluded: “While this possibility has not been ruled out, the weight of evidence reported here argues strongly that the current use of Bt crops is not associated with CCD.”
Like all science, that conclusion is subject to revision if further evidence develops–but in the mean time, I’m not going to jump to conclusions in the absence of physical evidence.
Some insecticides do affect bees more than others–this is why you can put Sevin powder on your dog, but it shouldn’t be used on your garden.
The biggest problem with researching insecticides as causal agents for CCD is bee biology: bees store pollen and honey for long-term use. This means that there might be a delay of days or months before contaminated provisions are fed to the colony. Linking symptoms to when an actual exposure to pesticides occurred is extremely difficult.
Nicotine-based pesticides, especially Imidacloprid, have been blamed in Canada as a cause of CCD. However, all the evidence -To Date- is based on surveys of beekeepers. No systematic analysis of bee bodies and honey has been conducted.
Most work on Imidacloprid bee toxicity has been conducted in Europe, and close collaboration between the US and EU scientists may produce new information.
Fungus, Parasites, AIDS, Immune Deficiency, etc.
Several press releases in the last couple of months have suggested either a fungus or a protozoan parasite as the culprit for CCD. Most of these are talking about the same organism–Nosema. There are several species of this organism that are parasitic on bees–it’s not a new occurrance.
Part of the confusion comes from the unclear taxonomic status of Nosema. It has been classified for many years as a Protist, but genetic data now suggests it’s linked to Fungi. This is why the two causes–fungal and parasitic–are actually the same.
American honey bees have been attacked by a variety of parasites (Varoa Mites, Tracheal mites), diseases, and viruses over the last 40 years. It is unknown at this time if an interaction between all these different causes could be causing enough stress for immunosuppression. One thing is clear–the different parasites and viruses aren’t found in all colonies that have CCD. Again, time and more evidence are needed.
I am thrilled the media and the public are finally realizing that we owe much of our food supply to my tiny little friends. But, unfortunately, the media need for a sound bite doesn’t convey this information well. We’re just going to have to be patient for more information, and more systematic data gathering.
Many things in life don’t have one simple, primary cause. This appears to be one of them.
If you want to read more:
- Official CCD Working Group Report
- Wikipedia entry on Colony Collapse Disorder *
- Xerces Society Information on Native Pollinators
*Normally I don’t use Wikipedia as a source, since it’s a dynamic reference. You never know if what you link to one day will change to “your mom is the Jamestown settlement.” However, this article is monitored and edited by two entomologists.
**Because this is written for a lay audience, apiculturists should not get their adeagus in a twist if I oversimplify bee husbandry.
EDITED TO ADD: additional updated info here, including podcast!