Summer grass; winter worm

Summer grass; winter worm

Natural treasure

Summer grass; winter worm

According to two recent research papers, the unsustainable extraction of ‘yartsa gumba’, or caterpillar fungus, may lead to setbacks in forest conservation in the Himalayan region, even as declining availability leads to lower incomes for those involved in its harvest. Some form of regulation needs to be put in place for the collection of this prized biological resource before it vanishes, writes Meera Iyer

In the high Himalayas of Uttarakhand, as the winter snows begin to melt in early May, a mini exodus occurs in villages in the shadow of these mountains. Every year, men, women and children trudge up to the higher hills, to altitudes between 3,500 and 5,000 m, where they join tens of thousands of others to camp there for five-six weeks.

They spend most of this time on their hands and knees, scouring the sparse vegetation for what looks like a stalk just a few inches high. When they find one, they carefully dig it up and out emerges what looks like a caterpillar with a twig sprouting from its head. This bizarre and somewhat repugnant creature is said to be the world’s most expensive biological resource. Locally known as keeda or keeda jadi, meaning insect or insect grass, it is better known elsewhere as the caterpillar fungus or by its Tibetan name yartsa gumba, meaning summer grass, winter worm. Its scientific name is Ophiocordyceps sinensis.

According to two recent research papers, its unsustainable extraction may lead to setbacks in forest conservation in the Himalayan region, even as declining availability leads to lower incomes for those involved in its harvest.

O. sinensis grows only in the alpine regions of the Himalayas that have annual precipitation of more than 350 mm, in and around the Tibetan plateau, Nepal, China, Bhutan and in parts of Uttarakhand and Sikkim. Until a few decades ago, only Tibetan nomads and Chinese medicine knew of it. Chinese medicine has prescribed it as a panacea for various ailments since about the 14th century. But in the 1990s, when some Chinese athletes attributed their success in international competitions to yartsa gumba, demand began to soar. In the early 2000s, it became famed for its supposed aphrodisiac qualities and acquired the moniker Himalayan Viagra, leading to another surge in demand. In Tibet, between 1997 and 2008, the price of yartsa gumba increased by an astonishing 900 per cent.

Most of this demand is met by China and Tibet; current estimates say India accounts for less than two per cent of world trade. But even so, a gold rush of sorts is underway in the Indian Himalaya. Rajendra Singh Rawat, ex-soldier and former gram pradhan of Shankadhura village in Pithoragarh district, describes how “the whole hilltop will be full of people” during collection season. Even children take a month off from school for the harvest because their sharp eyes can spot the elusive prize easier than adults. The money makes it all worth it. A kilogram of the fungus — between 3,500 and 4,000 pieces — sells for about Rs. 10 lakh.

Chandra Kuniyal and Rakesh Sundriyal from the Herbal Development and Research Institute in Gopeshwar, Uttarakhand, studied the dynamics of extraction of the caterpillar fungus in six villages in Garwhal. Their report, published in the journal Ecosystem Services in February this year, says that more than half the households surveyed harvested the fungus. In six weeks, these families earned between 1.4 to more than four times as much as they did from some of their other traditional activities such as potato farming. In other words, O. sinensis is an important source of income for many in Uttarakhand. It has improved living standards and seems to have been especially beneficial to poorer people, they say.

Mallika Virdi, social activist and a former sarpanch of Sarmoli village in Pithoragarh district, concurs. “Many of those involved in collecting yartsa gumba are people who have been pushed to the edge and are just trying to make a living,” she says. But the lucrative trade has also attracted people from outside the area. “People have traditionally harvested medicinal plants from the forest for hundreds of years. So there is some resentment that outsiders are now claiming what rightfully belongs to locals,” she says. Officially, local Van panchayats issue passes to local people for the harvest. But according to Kuniyal, “In practice, the majority of trade is carried out by non-local traders.” Or as Virdi puts it, “It’s like the Wild West up there.”

Lifecycle of the caterpillar fungus

The story of this much-in-demand medical marvel begins with the larva of a moth in the genus Thitarodes. This caterpillar is a root-borer that resides underground in Himalayan alpine areas. In the autumn, some of these caterpillars are parasitised by the O. sinensis fungus. Scientists don’t know whether the infection begins when a caterpillar swallows a fungal spore or if it occurs when a fungal hyphae penetrates the caterpillar. Regardless of how the infection begins, the fungus spreads through the larva and soon kills the caterpillar. Over the winter, a fruiting body begins to grow out of what was once the head of the caterpillar. In April or early May, this fruiting body emerges like a stalk out of the soil. But it is only from about late June to August that the fruiting body actually starts releasing spores.

And herein lines one of the problems with the harvesting of the caterpillar fungus. According to traditional Chinese medicine, yartsa gumba’s potency is greatest when the fruiting body is not too long in relation to the larval body and the dead larva is still firm. By extracting in May, harvesters can pick caterpillar fungi where the nutrients from the dead larva have not yet been completely used up, so that its body is still firm to the touch and the fruiting body is not yet too long. This means that the fungus is usually harvested before it has started sporulating.

So far, few studies have investigated the impact of collection on the population of the caterpillar fungus. But anecdotal evidence suggests drastic population declines. In March this year, Uttam Shrestha and Kamal Bawa of the University of Boston, Massachusetts, reported in the journal, Biological Conservation, how in Dolpa, Nepal, the average annual collection per person dropped from 427 pieces in 200 to just 123 pieces in 2010, a drop of more than 32 per cent in five years. Local harvesters told the researchers that though demand for the caterpillar fungus was increasing, the supply itself seemed to be decreasing, an opinion that Kuniyal and Sundriyal also heard.

The increasing demand and collection of yartsa gumba could also have other environmental impacts. Kuniyal and Sundriyal allude to the threat of an increase in exploitation of other forest resources like timber, wildlife and other medicinal plants, if caterpillar fungus populations are depleted. So far, research has not addressed the possible impact of about 10,000 people camping in ecologically fragile alpine zones. Surveys in Nepal and Bhutan have reported how 80 - 100 per cent of harvesters use fuelwood for their fires, including from slow-growing Rhododendron species that grow in the area. Camping sites are also littered with garbage at the end of the season.

Clearly, some form of regulation needs to be put in place for the collection of this prized biological resource. Kuniyal and Sundriyal suggest rotational harvests. Meanwhile, in China, researchers are experimenting with the possibility of growing the fungus in the lab, but so far, their results are not encouraging. One hopes that this medical marvel, recently credited with anti-aging properties, is not itself doomed to a shortened existence.