There is a slowly growing consensus, by some beekeepers anyway, that they know what causes Colony Collapse Disorder is. And the more they find out about this beast -- a pathogen -- the more convinced they are. Well, most of them anyway.
The thinking is that at the heart of the problem is this new Nosema cerane disease that has reared its ugly head and invaded our beehives.
Nosema is a tiny, tiny creature, a microscopic protozoan-like animal that goes from
place to place host to host as a very tough little spore. Weve had one species of this animal in the U.S. for years and years called Nosema apis. It was a problem, but not much of one. To become infected, an adult honey bee consumes some of those spores, received either from another infected bee or picked up while cleaning the hive. This can be somewhat common in the late winter and early spring when there are fewer bees in a hive and they are confined indoors because of the weather. Nosema is more of a problem for bees in the north with its winters, than for bees in the south which lets them off easy during that time of year.
When the spores are ingested they eventually migrate to the lining of the honey bees stomach where they embed themselves and begin to grow. There they attack and consume the cells that make up the lining and as these cells are destroyed the honey bees are less and less able to digest and absorb food. This is why infected bees die at a younger age about a week younger ... week five out of a normal six. They just cant get enough food. Obvious signs of an infection are almost nonexistent, although sometimes a severely infected colony will show signs of dysentery in the spring, but this ailment can be caused by other problems as well, so its difficult to tell. There is some indication that the wounds caused when these cells are destroyed are a pathway for viruses to enter the rest of the body of the bee, but thats yet to be proven.
As awful as this sounds its not usually a severe problem. It is often likened to high blood pressure because it is debilitating without significant outward signs.
This new cousin though, this one is a killer.
At first, Nosema cerena behaves much like its more docile relative Nosema apis. It, too, travels as a spore and is ingested by adult bees. Once in, it heads to the same location and like Nosema apis, this creature attacks the stomach lining ... but then it continues attacking internal organs and tissues. It becomes very destructive, and it multiplies at a very rapid rate, spreading spores all over the place. These spores are discarded by the infected bee both inside and outside the hive and they are fed to other bees. The scary thing about this is that infected bees dont really show problems other than not living as long as they should. But as more and more bees become infected, the number of adult bees that are dying begins to rapidly increase, and soon more are dying than are being born and the colony population essentially collapses, leaving a queen, lots of brood, and a few young bees ... does this sound familiar?
These wounds, too, are suspected of allowing viruses to enter the scene and become established especially since they are so much more severe, and once in they do their dirty work. Some of the common honey bee viruses, when given free rein in a wounded bee can make very short work of their host. So add to bees disappearing because of this new Nosema disease, and perhaps some disappearing because of infections of viruses and the probability that a colony will show some sort of population decline is inevitable.
Some assume this is the beginning and end of CCD. Perhaps they are right. A severe disease, an internal wound, an opportunistic virus and eventually an empty colony.
Another bit of support they have is that if beekeepers control this disease Nosema cerena in their hives, the collapse syndrome seems to pretty much go away. Break the cycle and you break the back of CCD.
Some think theres more to it than that, while others want more details: What virus, for instance, can do this? One of the old ones? A new one?
Meanwhile, some are still looking at the role agricultural pesticides could be playing in this mess, and even though its looking more and more like thats not in the CCD equation, they are still at the top of the list of Things Beekeepers Hate.
For this fall, sage advice for beekeepers is to control the newest menace on the block, that nasty Nosema cerena. No matter what CCD is caused by, youll be glad you did.
Enter your city or zip code to get your local temperature and air quality and find local green food and recycling resources near you.