Bees are among the most hardworking creatures on the planet. But in many parts of the world, honeybee colonies are declining so quickly that even the United Nations is worried. About two-thirds of the crops that feed the world rely on pollination by bees and other insects. Without them, we’d be looking at an agricultural doomsday scenario. And this is exactly what a University of Maryland professor wants to avoid – with the help of an army of tiny drones.