Bees are critical to ensuring our food supply, yet they are disappearing at an alarming rate. Over thirty percent of our agricultural crops depend on bees for pollination, and bee pollination means about $15 billion in agricultural production for the United States. But the number of bee colonies has fallen by 45 percent in the last 60 years. In 2006, US beekeepers noticed something they've never seen before -- massive bee die offs. Every year since 2006, one third of bee colonies in the United States disappear. This mysterious bee die off came to be called colony collapse disorder. Colorado beekeeper Tom Theobald explains explains what's behind bee disappearance and what we need to do about it.