Being a bee is hard. I'm speaking specifically of the honey bee, Apis mellifera, the one that produces the honey you buy in the store. Many insects, and other critters, eat by finding food and then eating it, and then they do that for a while and now and then reproduce by finding a mate, laying eggs that they perhaps put in a good location but thereafter leave alone, etc. etc. But honey bees do all of these thing in a way that makes it seem like they are trying to make it harder for them than it is for everyone else. Much of the food that honey bees eat is gathered at rare and hard to find sites (flowers), carried back to a central place that may be quite far away, then processed. Offspring are produced by a very small subset of a large colony, using a system involving several individuals who make places for the queen to lay the eggs around. Larvae are then taken good care of and fed. This whole thing takes place in a hive which can only be effectively placed in one of a limited number of locations. Since there is processed food (honey) and larvae (also good to eat) all in one place, the bee colony must have multiple ways of protecting itself, including picking a good location, making the hive hard to get into, and having a hoard of suicidal stingers ready to die in defense of the nest. Beyond this, sneaky invaders, other insects that might try to sneak into the hive, must be identified by guards.
Navigation over long distances, communicating with other bees about newly found hard to get and far away sources of food, mechanisms of controlling reproduction within the colony, thermoregulation of the hive, building and maintaining architecture, species recognition, a mechanism of changing behavior among a number of different tasks (thermoregulation, foraging, building the hive, attacking selected invaders, swarming) ... Yeah, being a honey bee is hard.
Colony Collapse Disorder (CCD) is a thing where the colonies of bees in a given area are affected by something that causes the number of bees to reduce in population over time ... the worker bees seem to disappear ... so the colony dies. Think about all the things I mentioned above. Any small subset of these things could be disrupted to cause something like CCD. The transfer of information about where to go to find food, and the process of foraging and navigating to food sources and back involves a lot of different mechanisms; the disruption of any one or two of those mechanisms might cause worker bees to fly off and not come back. The process of foraging at distance and carrying back food requires a great deal of energy. Any part of the process of maintenance and distribution of food to worker bees could cause them to starve or reduce in energy level, causing them to not return to the hive. Leaving most of these tasks and mechanisms untouched and operational but adding a pathogen that demands more energy from individual bees could have a similar effect. In other words, in the absence of any good information about what causes CCD, it would be very hard to come up with a simple explanation for that phenomenon on the basis of what bees do normally. The phenomenon can also be caused by any two or three of a dozen things, such that the cause in any given case could be very different from the cause in a different case.
To this we can add another feature of honey bees. For the most part, we are talking about bees that are not living in their native habitats. Our honey comes from a subset of honey bees that have been to varying degrees domesticated, and that are living in a climate that is not where they originally evolved. Imagine going to a region where chickens are grown but that is environmentally very different from the region where a chicken like bird lives normally, and deleting one or two of the key things we do to keep those chickens alive. I.e, leave all the chickens out for the winter in Montana. Not feed them. Etc. There would be "Coop collapse disorder" in no time. The fact that honey bees exist in a sort of liminal state of wildness (they forage in the wild, although the "wild" may be human maintained farm fields and orchards) and domestication (their hives are generally built and maintained by humans who may also provide heat and protection from predators) together with the fact that honey bees have undergone some degree of selection (to make them a bit less fierce, for instance) may mean that the complex web of physiological and behavioral adaptations that make bees "work" properly is somewhat more delicate than it might be for wild bees living in their native tropics.
I don't mean to give the impression that bee experts have no idea what causes CCD. They do have ideas, evidence, and there has been a fair amount of research done (below are links to a few key blog posts that summarize much of this). The point I'm making here is that the complexity of CCD and the difficulty in understanding this phenomenon should not be a surprise.
Just now, the European Union has decided to implement a regulation that bans a certain kind of insecticide, neonicotinoid, from use in their purview, because it is possible that this insecticide has a negative impact (perhaps multiple negative impacts) on bees, contributing to CCD. This may be a good idea, even if the insecticide in question is not "the" primary cause of CCD, if the chemical simply makes CCD a much more likely thing to happen. Banning it may be like giving a patient with some horrid infection an IV of fluids. The IV is not directly treating the infection, but the patient may require the support provided by the IV (and other things they do for you in a hospital, like the great food and a TV strapped to the ceiling) may be what it takes to allow other treatments, or the patient's own immune system, to bring the individual to a state of better health.
The ban was not universally supported. Voting against the bad were the United Kingdom, the Czech Republic, Italy, Hungary, Romania, Slovakia, Austria and Portugal; voting for the bad were Belgium, Bulgaria, Denmark, Estonia, Spain, France, Cyprus, Germany, Latvia, Luxembourg, Malta, the Netherlands, Poland, Slovenia and Sweden. Ireland, Lithuania, Finland and Greece abstained. This resulted in a vote that would not automatically institute the ban, but a decision by the controlling commission to move forward with the ban was made possible, and that is what has happened. The ban will run for two years and apply to flowering crops that normally attract bees. In a way, this is more of a giant experiment than an actual ban.
The Guardian reports:
Europe will enforce the world's first continent-wide ban on widely used insecticides linked to serious harm in bees, after a European commission vote on Monday.
The landmark suspension is a victory for millions of environment campaigners concerned about dramatic declines in bees who were backed by experts at the European Food Safety Authority (EFSA). But it is a serious defeat for the chemical companies who make billions a year from the products and also UK ministers - who voted against the ban. Both had argued the ban will harm food production.
Tonio Borg, health and consumer commissioner, said: "Our proposal is based on a number of risks to bee health identified by the EFSA, [so] the European commission will go ahead with its plan in coming weeks. I pledge to do my utmost to ensure that our bees, which are so vital to our ecosystem and contribute over €22bn annually to European agriculture, are protected."
It is almost certainly not the case that bee researchers unanimously agree that neonicotinoid is the most important cause of CCD or that banning it will work. Neonicotinoid is actually a good kind of insecticide because it works by being taken up by plants, and thus, targets invading insects selectively, and also, affects insects that are not bothered much by other insecticides because the insects bore into the plant. So, there may be some serious consequences to agriculture in Europe caused by this ban.
It will be interesting to see what happens over time. I'm not sure how long it will take for the ban to fully take effect. Since it is added to soil, neonicotinoid will remain "in use" for a while after it is no longer applied. And, even if neonicotinoid was a key cause of problems in bees, it is quite possible that other causes were exacerbated by neonicotinoid use, and the effects of those causes may take longer to go away or become less important.
One interesting aspect of this ban is the way in which environmental groups and the chemical companies that make the insecticide have bifurcated into two distinct ways of thinking. Again, from the Guardian:
Greenpeace's chief scientist, Doug Parr, said [of a dissenting vote by the UK]: "By not supporting the ban, environment secretary, Owen Paterson, has exposed the UK government as being in the pocket of big chemical companies and the industrial farming lobby."...
But a spokesman for Syngenta, which makes one of the three neonicotinoids that have been suspended, said: "The proposal is based on poor science and ignores a wealth of evidence from the field that these pesticides do not damage the health of bees. The EC should [instead] address the real reasons for bee health decline: disease, viruses and loss of habitat."
Prof Simon Potts, a bee expert at the University of Reading, said: "The ban is excellent news for pollinators. The weight of evidence from researchers clearly points to the need to have a phased ban of neonicotinoids....
"Bayer remains convinced neonicotinoids are safe for bees, when used responsibly and properly," said a spokesman for Bayer Cropscience. "As a science-based company, Bayer is disappointed that clear scientific evidence has taken a back-seat in the decision making process."
Both Bug Girl and Carl Zimmer have written a fair amount on this topic, and their posts include links to a great deal of additional information.
- 2012-03-29 Carl Zimmer in the New York Times: 2 Studies Point to Common Pesticide as a Culprit in Declining Bee Colonies
- 2012-03-31 Bug Girl's Blog: Are Neonicotinoid Pesticides Killing Bees?
- 2012-05-23 Bug Girl's Blog: Bees and Pesticides (again)
Bees do not actually move eggs. The queen lay the egg in an empty cell. The larva hatches in the same cell. It is fed until it is ready to pupate then the cell is closed with wax.
In CCD something is killing bees in the field or impairing their ability to find the hive. Extra energy expenditure is easily noted in reduced honey crop. Merely damaged bees die also in the hive and can bee examined. So it is none of these.
Neoinicotinoids apparently impair the bees orientation ability long before it is killed. This conforms really well with the observed result. The bees that find the hive are fine. At least until the next trip.
Also, I'm surprised no one has commented on this, bees that navigate poorly will enter the wrong hives much more often. And being laden with pollen will be admitted by the new hive. This is a vector for other deceases! It could very well be that affected zones have much higher spread of other deceases than normal. Someone should study this.
Ah, you are right, thanks. I was thinking of ants.