According to an article by Dr. Mercola:
"Honeybees are perhaps one of the least recognized workers in the agricultural industry. They contribute $15 billion in annual agriculture revenue to the U.S. economy alone, as a full one-third of the U.S. food supply depends on them pollinating crops.
"Apple orchards, for instance, require one colony of bees per acre in order to be adequately pollinated. So, unless the mysterious disappearance of bees is reversed, major food shortages could result."Read more: http://bit.ly/qBhgKy
However, ecological changes would be just as drastic with the loss of all cats.
"Cats play a critical role in keeping the rodent population down. If there were no cats, we'd be overrun with rats."