From the New York Times:
"More than a quarter of the country's 2.4 million bee colonies have been lost - tens of billions of bees, according to an estimate from the Apiary Inspectors of America, a national group that tracks beekeeping. So far, no one can say what is causing the bees to become disoriented and fail to return to their hives.
...Honeybees are arguably the insects that are most important to the human food chain. They are the principal pollinators of hundreds of fruits, vegetables, flowers and nuts. The number of bee colonies has been declining since the 1940s, even as the crops that rely on them, such as California almonds, have grown. In October, at about the time that beekeepers were experiencing huge bee losses, a study by the National Academy of Sciences questioned whether American agriculture was relying too heavily on one type of pollinator, the honeybee."
full story here