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Cordyceps sinensis - Yartsa Goenbub in Bhutan
Highly valued medicinal plant
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Summer grass-winter worm
Cordyceps sinensis
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Yartsa Goenbup - Summer grass-winter worm
Yartsa Goenbub roughly translates as 'Summer Grass-Winter Worm'
Dr. Jones digs a fungus

Dr. Nigel Hywel-Jones, insect pathologist and advisor to the agriculture ministry on poaching problems with Yartsa Goenbub, and his research team studying the fungus contributed this article.
Some 15 years ago few people in the west had heard of Cordyceps sinensis - literally the Chinese Cordyceps. This is the scientific name for what is known in Bhutan as Yartsa Goenbub.

Yartsa Goenbub roughly translates as 'Summer Grass-Winter Worm'. A 'grass' is a plant while a 'worm' is an animal. Biologically, Yartsa Goenbub is neither.

It is a fungus - related to a humble mushroom that we can buy in the market. And related to a 'toadstool' that our parents told us, as children, was deadly to eat, or even touch. Although not deadly to us, Yartsa Goenbub is as deadly as the deadliest 'toadstool' to its insect host.

Fifteen years ago, because of the success of Ma Junren's athletes in breaking middle and long-distance world records, there was increased demand for the Chinese Cordyceps. Ma Junren acknowledged that Yartsa Goenbub was an important tonic for the athletes - improving physical performance.

Now, a casual 'Google' for "Cordyceps sinensis" gives 8000+ internet hits! Many westerners are adopting the more 'back-to-nature' approach of their ancestors. Consequently, the last fifteen years has seen an increase in the demand for 'alternative medicine'.

To feed this demand there has been pressure on Yartsa Goenbub populations which were traditionally harvested from the alpine grasslands of the Himalayan Plateau. Most collecting was from Tibet, but more recently, Tibetan poachers found it profitable to cross the border into Bhutan and steal this valuable commodity. We can only guess at how much Yartsa Goenbub has gone out of Bhutan in the last ten years and more.

The discovery of Yartsa Goenbub is lost in the mists of time. But it is thought that some yak herders noticed that when their yaks fed in particular areas of grassland where the Yartsa Goenbub occurred, their yaks recovered more quickly from the rigor of the harsh winter. The yak herders possibly started collecting it and eating this themselves, finding that it gave them a boost when walking in the mountains.

Cordyceps sinensis

By word-of-mouth, the detail of this wonder tonic eventually reached the Chinese Royal Court about one thousand years ago. For hundreds of years Yartsa Goenbub was used in Traditional Chinese Medicine.

But only the Emperor and his immediate court could use it. It has only been in the last few hundred years that it has trickled down to the ordinary man on the street. But so expensive has it traditionally been, only the well-off could afford Yartsa Goenbub.

Yartsa Goenbub is not eaten on its own. In herbal medicine it is cooked with meat (usually duck or chicken) to help lung, kidney and heart function. When Yartsa Goenbub is cooked with pork it prevents impotence making it a natural Viagra! Cordyceps sinensis can be found in herbalists' shops throughout East Asia. I have seen it on sale in China, Hong Kong, Japan and Thailand. Thai supermarkets sell small jars of 'chicken essence and Cordyceps' tonic drink. However, it is the recent move into new markets (especially North America and Europe) that has put a large strain on demand.

Cordyceps Sinensis

Yartsa Goenbub is a fungus that has learned how to invade and kill insects - it is the HIV of the Insect World. The small brown fruit bodies emerge from their winter dormancy around late May. The commercially valuable ones are young fruit bodies before they make their spores. Late May and June is therefore a good time for collecting these. As they mature over the next four to six weeks they swell, producing millions of spores that are shot from the fruit body to land on surrounding vegetation.

These are then picked up by grazing caterpillars. The mature fruit bodies, shooting their spores in late June and July, are biologically valuable - although considered poor quality in the market.

Spores on the grazing caterpillars invade using enzymes. Once inside, Cordyceps sinensis battles the insect immune system. If Cordyceps sinensis wins then it slowly feeds on the fat reserves. The host is the larval stage (caterpillar) of a moth.

The caterpillars live under the soil feeding on the vegetation of the alpine meadows. As they feed they store nutrients so they can make the change from larva to pupa and finally to adult moth.

A mature larva will pupate and develop in early spring. Healthy pupae emerge as adults in the summer, so completing the life-cycle. The ones killed by Cordyceps sinensis emerge, instead, as the valuable fruit bodies of Yartsa Goenbub so completing the fungus' life-cycle. This relationship between insect and fungus has been going on for millions of years - a relative of Cordyceps sinensis was found in fifteen million year old Dominican amber infecting an ant.

Cordyceps Sinensis
There are 400 species in the genus Cordyceps. Very few of these species have been able to adapt to life in grasslands with most Cordyceps found deep in dark, moist forest. Although Cordyceps sinensis is only found above 4000 metres in Bhutan there are certainly many tens of Cordyceps species in Bhutan's tropical forest below 2000 metres. In Thailand there are over 120 Cordyceps species.

Many infect caterpillars like Cordyceps sinensis. Others infect beetle larvae, ants, wasps, termites and flies. Importantly, all Cordyceps (including Cordyceps sinensis) are very specific in what they will infect. In alpine grasslands, Cordyceps sinensis will only infect hepialid larvae. They can not infect any of the tens of other species of moths and butterflies that can be seen flying through these meadows in the summer months. But occasionally, cross-over occurs - in much the same way that Bird Flu has crossed over to humans. At some point a forest-dwelling Cordyceps, probably infecting a relative of the alpine-meadow moth, moved out of the forest and into the grassland.

What is the future of Yartsa Goenbub in Bhutan? With the relaxing of previous collecting bans, the last few years has seen a mini Klondike Gold Rush into the hills of Bhutan. With my friend Mr. Tshitila of the Renewable Natural Resources Centre (Yusipang) we have spent several seasons studying the populations in the Soe and Lingzhi area of Northwest Bhutan.

With support from Dr. Paul Cannon of CABI Biosciences we have been able to secure three years research in the hills from the UK Government Darwin Initiative. Research will help us to more fully understand the dynamics between the fungus, the caterpillar and those collecting in the mountains.

This article was contributed by KUENSEL, Bhutan's national newspaper 2006

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