The World’s Most Valuable Parasite Is in Trouble

Ten years ago, Kelly Hopping was driving through a Tibetan mountain pass when her Chinese colleague stopped the car, hopped out, walked to a roadside stall, and returned with what looked like a bag of Cheetos on sticks. Each orange lump was, in fact, a dead caterpillar whose body had been overrun by a fungus (the stick). Hopping’s colleague, whose mother had cancer, had bought them for their medicinal value—and he had parted with an astonishing $1,000 for about 250 pieces. “My mind was blown,” says Hopping, an ecologist at Boise State University.

The caterpillar fungus, , is the world’s most valuable parasite. It’s a relative of the that , but unlike its infamous cousin, it is found only on the Tibetan plateau, where it infects the larvae of . It has long been part of traditional Chinese medicine, and demand for it has risen so sharply in recent decades that in Beijing it