A ravenous swarm stretches as far as the eye can see. It has no leader or strategic plan; its only goals are to eat, breed, and move on. These are desert locusts— infamous for their capacity for destruction. But most of the time desert locusts are no more dangerous than grasshoppers. So what does it take to turn these harmless insects into a crop-consuming plague? Jeffrey A. Lockwood investigates.

[TED Ed]