Parasitic fungus fetches increasingly high prices in Chinese markets

Rhinos and elephants have long been targeted by poachers for the keratin and ivory that grows from their heads. Horns and tusks are ground up and sold for imagined medicinal value, primarily in China, often at the cost of the animal’s life. The latest miracle cure to be sold in this way also grows out of an animal’s head, but in this case, it’s the growth itself that causes the animal’s death, not the poaching. That’s because the prize in question is a zombifying fungus that can only be found growing out of the heads of infected, dead caterpillars.

The fungus is known as Ophiocordyceps sinensis, a parasite that can be found on insects in Tibet and the Himalayas. Once a caterpillar is infected, the fungus slowly grows and takes over their body, making it increasingly rigid in the process. After hiding out in a caterpillar like Thitarodes damxungensis for the winter, the fungus will finally kill its host, growing a spore-filled stalk out of the caterpillar’s head. If other caterpillars are nearby, they’ll then be in range for subsequent rounds of infection by the spores.

Finding fewer fungi

However, finding infected caterpillars is becoming increasingly difficult. Rising prices on fungus-carrying caterpillars has been a big motivator for many people, and at this point the caterpillars have been so over-collected that the fungus O. sinensis has been designated an endangered species in China. Once on sale in China, the dead, infected caterpillars can sell for close to $9,000 a pound, although many people will by smaller helpings to cook into a soup or tea. While there are some similarities to other expensive fungi, like truffles, the market for dead caterpillars isn’t looking for a meal as much as a cure for everything from cancer to, of course, erectile dysfunction.

As the caterpillars and fungi continue to be harvested, some people are speculating that the market for these supposedly medicinal corpses may be crashing soon. That may require more enforcement of conservation laws, but it may come about on its own if there just aren’t enough dead caterpillars to sustain interest in misinformed public.

Source: The worms that cost $20,000 a kilo by Veronique Greenwood, BBC Future