Cooperation is usually a good thing. It’s something we’ve all been encouraged to do since childhood. I’m pretty sure there’s even a Sesame Street song about it. But when it involves insects important to the future of our food supply, cooperation between a fungus and a virus is anything but positive.
In 2006, apiarists began discovering honeybee hives that were suddenly empty, with maybe the queen and a few worker bees left. These deserted hives were left filled with resources, and no dead or dying bees were found nearby. Beekeepers were baffled. It seemed the bees just flew away and died. Such disappearances, now called colony collapse disorder (CCD), have gone on to affect 20 percent to 40 percent of hives in the United States.
Why do we care so much about the honeybees? Roughly a third of our food supply requires bees for pollination, which amounts to as much as $15 billion worth of value to the American farmer. Many of the nuts, fruits and vegetables we love – almonds, apples, blueberries, squashes – depend on the honeybee. If the bees keep disappearing, food producers could be in trouble.
The mystery of CCD, which has occurred in most of North America and in Europe, has yet to be solved. Many possible culprits have been examined, from viruses, mites and fungi to pesticide exposure and climate change, to no avail. One virus looked promising and a fungus was put forward, but both were found to be present in non-CCD hives as well as those that had collapsed.
Recently, a disparate group of scientists made great inroads into the mystery, through cooperation of their own. A group of U.S. Army scientists and bee experts from Montana put their heads together to see if they could identify a culprit.
The Army scientists work at the Edgewood Chemical Biological Center, where they look for nonmedical ways to keep us safe from chemical and biological elements. This team, led by Charles H. Wick, is working on software to help protect soldiers in the field from anything biological. They use mass spectrometry to identify the proteins in a sample, then compare the findings to a database of viruses and other microscopic life-forms. Think of your brain as a database of smells. Even if someone hands you a piece of paper that looks nothing like a rose, you can still identify the smell of a rose by comparing the new data to what you’ve already catalogued. The mass spectrometer is your nose, and the database of microorganisms is your brain.
To uncover what’s killing bees, researchers took samples from healthy and collapsing colonies in the form of dead bees (apparently a coffee grinder worked best to make bee paste) and compared the proteins to the database of microscopic creatures. The team discovered that a fungus, Nosema ceranae, and a virus, invertebrate iridescent virus (IIV), were both present in all the colonies that collapsed. They were present in other colonies, but were found together only in the ones that collapsed. The bee expert team then introduced the virus and the fungus to some healthy bees to see what would happen, and they died more quickly than bees with the fungus or the virus alone.
The mystery is far from solved, however. We still don’t know the exact way the colonies catch the fungus and virus – whether one weakens them and the other finishes them off, or if they catch both simultaneously, or if something environmental weakens them and makes them susceptible. In any case, we seem to have come a few steps closer to fully understanding the problem, which will hopefully lead to a solution before it’s too late.
While she admits to having placed insects in jars in the freezer, Web Editor Jenn Nemec has never put one in a coffee grinder.