Winter Worm, Summer Grass

The worm, Lhamotso explains, “has changed our lives.” What Tibetans call the worm is actually not a worm but a fungus — Cordyceps sinensis — that feeds on caterpillar larvae. Or, to give the fungus its more poetic name, “winter worm, summer grass,” because its appearance changes from one to the other with the seasons.

The worm is a prized ingredient in traditional medicines here, with prices in the past few years skyrocketing: prime specimens are worth their weight in gold, literally, about $900 an ounce. Even the most ordinary pickings command prices rivaling that of French truffles, another famous fungus. Because the caterpillar fungus is indigenous only to the 1,000-mile-long Tibetan plateau running from western China to Nepal, the money has hastened the nomads’ lurching transition into modernity. “Like a gold rush in the Wild West, it’s brought enormous wealth to these communities,” says Andrew Fischer, an economist specializing in Tibet at the London School of Economics.

For centuries, Tibetan nomads added caterpillar fungus to soups or tea, believing it boosted stamina, endurance, lung capacity, kidney function and, of course, sexual performance.

More recently, Houston Rockets basketball star Yao Ming revealed that he too is a fan of the fungus. Then came the 2003 epidemic of SARS, sudden acute respiratory syndrome, and Asian consumers bought anything that might boost immunity and the fungus was all the rage. China, last year, exported $43 million worth of caterpillar fungus.

“Yes! Grandma & Grandpa, you may not be a world-class athlete shattering world records, but wouldn’t it be great to feel like one?” claims one promoter out of Canada.

The centre of the caterpillar fungus trade is in Qinghai province, particularly the Tibetan enclave of Golog. Here, the bu — Tibetan for worm — is by far the largest source of cash...