An unusual fungus is becoming increasingly important to the economy of Tibet, accounting for for over 8 per cent of its gross domestic product in 2004.
The caterpillar fungus, Cordyceps sinensis, is known locally as yartsa gunbu (“summer herb winter worm”) after the transformation that takes place when it devours its host, the ghost moth larva, following the latter’s hibernation under Tibet’s plateau grasslands. Larvae of the moth genus Thitarodes spend up to five years underground before pupating. The fungus attacks the caterpillar as it feeds on roots, filling the larva’s entire body with mycelium and eventually killing and mummifying it. A finger-length and pencil-wide fruiting body (or mushroom), dark brown to black, grows from the larva’s head and above ground where it releases spores.
The entire fungus-caterpillar combination is harvested by hand for medicinal use. It is highly prized in Tibetan and Chinese medicine, where it is used as an aphrodisiac and for a variety of ailments from fatigue to cancer.
Caterpillar fungus came to the world’s attention in 1993 when three Chinese athletes broke five women’s world records for 1,500m, 3,000m and 10,000m at the national games. Despite international scepticism, tests on the athletes revealed no illegal substances. Their coach told reporters that they were taking yartsa gunbu and turtle blood.
Yartsa gunbu is now the most important income source in rural Tibet, contributing 40 per cent of the annual cash income to local households. Prices increased 500 per cent between 1997 and 2006, and in 2007 a kilogram of the best quality product traded for the equivalent of over £16,300 — more valuable than gold.
The Tibetan government has earmarked caterpillar fungus collection as one of three industries it will focus on to revitalise the plateau after the earthquake that hit the region in April. But local communities’ growing dependence on the crop has led to violent confrontations between rival pickers and is fuelling concerns that the fungus may be over harvested.
