The declining populations of bees and other pollinators has been a topic of great concern for a number of years. There has not been general agreement on the root cause and, in fact, it appears as though there are multiple causes at play.
The decline of bee populations worldwide is a serious problem that threatens much of agriculture. From 2006 to 2011, losses in managed honeybee colonies in the U.S. averaged 33 percent a year. In recent years, beekeepers have had to replace 50 percent of their colonies each year.