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Locusts

They're the original insect plague. Humans have been battling these ravenous winged grasshoppers for millennia.



"All locusts are grasshoppers, but not all grasshoppers are locusts," Greg Sword, an entomologist at Texas A&M University, says. The behavior that separates locusts from their grasshopper brethren is swarming. A single locust isn't worrisome, and locusts like to live alone for most of their lives. But when a group of locusts swarm, they can devastate the vegetation of an entire region, devouring everything in sight. They only start to swarm when the locust population increases to the point that individual locusts are crowded together, triggering a dramatic change in behavior and coloring. Mature locusts begin flying along with the wind, eating as much as their weight (2 grams) in vegetation every day. In areas of Africa where subsistence farming is practiced, large plagues of locusts can devastate the food supply of a region. "They can potentially affect the livelihoods of one out of 10 people on the planet," Sword says.



Australia suffered a massive swarm of Australian plague locusts last year. This year, locusts are making an appearance in China and Central Asia. Here in North America, however, much of the locust threat subsided when the Rocky Mountain locusts went extinct in the early 1900s. "There used to be epic, sky-darkening outbreaks," Sword says. But the huge populations of locusts were probably destroyed by pioneers building towns along the riverbanks where locusts laid their eggs.