The Economist looks at new evidence that certain types of pesticides may be the cause of recent dramatic declines in bee numbers around the world:
In the winter of 2006 beekeepers in America noticed something odd—lots of their hives were dying for no obvious reason. As the months passed, reports of similar phenomena began coming in from their European counterparts. Mystified scientists coined the label “colony collapse disorder” (CCD) to describe what was happening. Since then, much brow-sweat has been expended trying to work out just what CCD really is.
Dying bees are a problem, and not just for apiarists. Bees pollinate many of the world’s crops—a service estimated to be worth $15 billion a year in America alone. And there is no shortage of theories to explain the insects’ decline. Climate change, habitat destruction, a paralysing virus, fungal infection and even a plague of parasitic mites have all been proposed. But one of the leading ideas is that the bees are suffering from the effects of neonicotinoids, a class of commonly used pesticides, introduced in the 1990s, which are toxic to insects but much less so to mammals.