For American agriculture, bees are valuable not for their honey, but for their pollination services--without them, you wouldn't have almonds, blueberries, tomatoes and a long list of other crucial crops. For this reason, bees are often hired out by the hive to pollinate farmers' fields. That means they are exposed to a wide range of pesticides meant to ward off other insects. But honeybees throughout North America have been dying by the millions for a decade now, often simply disappearing from their hives never to return. The phenomenon now known as colony collapse disorder has many possible culprits, from pathogens to pesticides.