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 and dictates the pace of daily life. Every year, several people are killed in turf battles over the bu, often ethnically tinged, pitting Tibetans against Hui Muslims, another minority, or against Han Chinese.

The best caterpillar fungus is found at higher elevations, places such as Heitushan, the 14,000-foot Black Earth Mountain in Golog where Lhamotso lives.

Lhamotso counts herself lucky to have the motorcycle to climb the mountain. She works alongside her daughters bringing down the fungus a little every day.

Although the dead caterpillar is rather unprepossessing in appearance, it’s not nearly as disgusting as it sounds: sort of like a little yellow root with a stalk growing out of the top. Reaching into the pocket of her faux leather jacket, daughter Hiriti pulls out a tissue and unwraps what looks like a 3-inch-long twig, the only piece she found all day. It will sell for about $3, but it could command a retail price of $10 in Singapore or Tokyo.

Lhamotso and the girls expect to make at least $6,000 this season — about triple what most Chinese families earn in a year. Last year’s take was enough that Lhamotso and her husband built their house, the interior wallpapered with photographs from magazines of an assortment of celebrities, movie stars, Mao Tse-tung, the Dalai Lama.

Lhamotso is well aware that fungus might not be a reliable source of income for much longer. The fungus is growing scarcer from over-harvesting and changes in the fragile ecosystem of the Tibetan plateau.

''For years, it’s been like digging up gold but more valuable,” says Daodu, 31, a teacher. “People today can’t survive without it.”