Ophiocordyceps sinensis

Morphological features Ophiocordyceps sinensis consists of two parts, a fungal endosclerotium (within the caterpillar) and stroma. The stroma is the upper fungal part and is dark brown or black, but can be a yellow color when fresh, and longer than the caterpillar itself, usually 4–10 cm. It grows singly from the larval head, and is clavate, sublanceolate or fusiform, and distinct from the stipe (stalk). The stipe is slender, glabrous, and longitudinally furrowed or ridged. The fertile part of the stroma is the head. The head is granular because of the ostioles of the embedded perithecia. In traditional Chinese medicine, its name is often abbreviated as chong cao (蟲草 "insect plant"), a name that also applies to other Cordyceps species, such as C. militaris. In Japanese, it is known by the Japanese reading of the characters for the Chinese name, , while in Korean and Vietnamese it is known by the transliterated forms of the Chinese word, dongchunghacho (동충하초) and đông trùng hạ thảo respectively. Strangely, sometimes in Chinese English-language texts Cordyceps sinensis is referred to as aweto, which is the Māori name for Ophiocordyceps robertsii, a species from south-eastern Australia and New Zealand. The English term "vegetable caterpillar" is a misnomer, as no plant is involved. "Caterpillar fungus" is a preferred term. Synonyms Since the 1980s, 22 species in 13 genera have been attributed to the anamorph (asexually reproducing mold-like form) of O. sinensis. Additional synonyms for the teleomorph are Cordyceps nepalensis and C. multiaxialis. They have similar morphological characteristics to O. sinensis, also had almost identical or identical ITS sequences and its presumed anamorph, H. sinensis. ==Ecology and life cycle==

The caterpillars prone to infection by O. sinensis generally live underground in alpine grass and shrub-lands on the Tibetan Plateau and the Himalayas at an altitude between . The fungus is reported from the northern range of Nepal, Bhutan, and also from the northern states of India, apart from northern Yunnan, eastern Qinghai, eastern Tibet, western Sichuan, southwestern Gansu provinces. During late summer, the fruiting body disperses spores. The caterpillars, which live underground feeding on roots, are most vulnerable to the fungus after shedding their skin, during late summer. In late autumn, chemicals on the skin of the caterpillar interact with the fungal spores and release the fungal mycelia, which then infects the caterpillar. The slow growing O. sinensis grows at a comparatively low temperature, i.e., below 21 °C. Temperature requirements and growth rates are crucial factors that distinguish O. sinensis from other similar fungi. == Use in traditional Asian medicines ==

, Southern Qinghai, China The use of caterpillar fungus as folk medicine apparently originated in Tibet and Nepal. So far the oldest known text documenting its use was written in the late 15th century by the Tibetan doctor Zurkhar Nyamnyi Dorje (Wylie: ) [1439–1475]) in his text: ("Instructions on a Myriad of Medicines"), where he describes its use as an aphrodisiac. The entire fungus-caterpillar combination is hand-collected for medicinal use. In traditional Chinese medicine, it is regarded as having an excellent balance of yin and yang as it is considered to be composed of both an animal and a vegetable. Wild-collected "cordyceps" is not always true O. sinensis, even when the location and the host insect matches. This has resulted in the description of new species such as Cordyceps liangshanensis (Liangshan, China; many Nepali "cordyceps" are also incorrectly identified to be this species, and no new names for them have been proposed yet) and Samsoniella hepiali (Qinghai, China). It is marketed for various health benefits but lacks sufficient scientific evidence for safety or effectiveness, and quality can vary due to inconsistent processing and labeling. Secondary metabolites A 2008 source reports that O. sinensis contains cordycepin, an adenosine derivative originally discovered in C. militaris. However, this study uses store-bought material labeled as O. sinensis without any molecular confirmation that it is indeed the species. A more in-depth 2017 study, which fully characterized the biosynthetic machinery for cordycepin, found that O. sinensis does not produce cordycepin. This discrepancy underscores the importance of correctly identifying "cordyceps" species. ==Economics==

In rural Tibet, yartsa gunbu has become the most important source of cash income. The fungi contributed 40% of the annual cash income to local households and 8.5% to the GDP in 2004. Prices have increased continuously, especially since the late 1990s. In 2008, one kilogram traded for US$3,000 (lowest quality) to over US$18,000 (best quality, largest larvae). The annual production on the Tibetan Plateau was estimated in 2009 at 80–175 tons. The Himalayan Ophiocordyceps production might not exceed a few tons. In 2004 the value of a kilogram of caterpillars was estimated at 30,000 to 60,000 Nepali rupees in Nepal, and about Rs 100,000 in India. In 2012, a pound of top-quality yartsa had reached retail prices of $50,000. advertising Dōng chóng xià cǎo (冬虫夏草) among other local specialties. The price of Ophiocordyceps sinensis is reported to have increased dramatically on the Tibetan Plateau, about 900% between 1998 and 2008, an annual average of over 20% (after inflation). However, the value of large caterpillar fungus has increased more dramatically than small Cordyceps, regarded as lower quality. == Impacts of wild collection ==

Societal impact Because of its high value, inter-village conflicts over access to its grassland habitats has become a headache for the local governing bodies and in several cases people were killed. In November 2011, a court in Nepal convicted 19 villagers over the murder of a group of farmers during a fight over the prized aphrodisiac fungus. Seven farmers were killed in the remote northern district of Manang in June 2009 after going to forage for Yarchagumba. Its value gave it a role in the Nepalese Civil War, as the Nepalese Maoists and government forces fought for control of the lucrative export trade during the June–July harvest season. == Cultivation ==

Mycelia Cultivated O. sinensis mycelium is an alternative to wild-harvested O. sinensis, and producers claim it may offer improved consistency. Artificial culture of O. sinensis is typically by growth of pure mycelia in liquid culture (in China) or on grains (in the West). Ophiocordyceps sinensis is now cultivated on an industrial scale for their use in traditional Chinese medicine. However, no one has succeeded so far in rearing the fungus by infecting cultivated caterpillars; an increase of five times compared to 2017. The selling price of fresh O. sinensis ranges from 10-20 million VND/kg, while dried O. sinensis ranges from 100-200 million VND/kg. Therefore, the economic value of cultivated "cordyceps" in Vietnam is estimated to be around 10,000 billion VND/year. In the period 2017-2022, the production of cultivated "cordyceps" has grown at an average rate of 40%/year. Fruiting body A fruiting body with a mature perithecium was first grown in laboratory conditions in China in 1983, using a growth media. By 2014, it was possible to obtain a mature fruiting body with a rice-based growth media in a low-altitude location. However, such amorphous culture media do not generate a product with the traditional presentation of "worm and grass". Inoculation of caterpillars leading to a fully mature fruiting body was reported in 1991. This led to an early form of cultivation: caterpillars were artificially inoculated with the fungus, then placed into the natural habitat to induce the generation of the fruiting body. This increased the yield of the product, but was still subject to climate variations. In 2016, it became possible to mature the inoculated insects in a controlled environment. O. sinensis cultivated this way has been commercialized in China. Vietnam, Taiwan, and Indonesia. The golden-colored fruiting body is eaten as an inexpensive mushroom. • Samsoniella hepiali mycelia is cultivated in China. It is used in two "Jinshuibao" products found in the Pharmacopoeia of the People's Republic of China and more than 260 healthcare products in China, with a total market worth of approximately 10 billion RMB. • Paecilomyces tenuipes contains acetoxyscirpenediol and ergosterol peroxide. In some traditional-medicine contexts, it is acceptable to include the above alternatives in the term "cordyceps" or . Li et al. (2023) (in Chinese) provides a more detailed overview of the cultivation of Cordyceps sensu lato globally. ==See also==