Cordyceps sinensis, also known as “winter worm summer grass” or “Yarza Günbu” in Tibetan, is a combination of “insect” and “grass”. The “insect” refers to the larval body of the moth family in the order Lepidoptera, while the “grass” refers to the fungus Ophiocordyceps sinensis in the family Clavicipitaceae.
Cordyceps sinensis is composed of two parts, the stroma and the insect body; the underground part of Cordyceps sinensis is indeed an insect, while the aboveground part is not “grass” but the fruiting body of the fungus, which refers to the stroma. Once it becomes Cordyceps sinensis, it will never turn back into an insect.
During winter, the fungus Cordyceps sinensis (a parasitic fungus belonging to the family Clavicipitaceae in the order Hypocreales) invades the larval body of the bat moth, absorbing its nutrients and causing the insect body to be filled with mycelium and die. The Cordyceps sinensis fungus continuously absorbs nutrients from the insect body and becomes a sclerotium. In early summer, the stroma of the fungus grows out of the head of the insect body and emerges from the ground. “Winter worm summer grass” refers to the insect-fungus complex formed through the above process.
In 2015, the most complete and well-preserved Han Dynasty marquis tomb complex in China was discovered in Nanchang, Jiangxi Province – the Haihun Marquis Tomb of the Western Han Dynasty (202 BC – 8 AD). Tens of thousands of precious cultural relics were unearthed, setting multiple archaeological records. Among them, there was a special discovery, a box containing Cordyceps sinensis that had been preserved for over 2000 years. This also means that the history of collecting Cordyceps sinensis in China has lasted for at least 2000 years.
Origin of the Name
“Winter is the insect, summer is the grass, winter worm summer grass is a treasure.” Winter worm summer grass, abbreviated as Cordyceps, is a fungus that parasitizes the larval body of the bat moth during winter and develops in summer. It is named as such because of this.
In terms of appearance, the body of the winter worm summer grass is golden yellow, light yellow, or yellowish-brown, and it is also known as “golden grass” due to its expensive price.
Main Production Areas and Environmental Conditions
Winter worm summer grass mainly grows in alpine meadows at altitudes of 3000-5000 meters, as well as grassy slopes near the snow line on the upper part of the mountain shrub belt. It is greatly influenced by altitude, climate, temperature, humidity, light, soil, vegetation, etc., with precipitation and temperature having the greatest impact.
It is mainly distributed in the high-altitude areas of Tibet, Qinghai, Sichuan, Yunnan, Gansu, and other provinces within the Qinghai-Tibet Plateau region, as well as in the high-altitude grasslands of neighboring countries such as Nepal, Bhutan, and India in the Himalayan mountain range.
The quality of winter worm summer grass generally follows a rule: the higher the altitude, the better the quality of the Cordyceps.
In terms of appearance, the best quality Cordyceps are found in Yushu, Qinghai, and Nagqu, Tibet. Qinghai’s Golog prefectue and Tibet’s Chamdo regions follow closely. Some Cordyceps from the Aba Tibetan Autonomous Prefecture in Sichuan also have good quality, while others, such as Qinghai’s Haidong region, Tongren, and Guide, as well as Nyingchi City in Tibet and Bayi region, have relatively poorer quality.
The Qinghai-Tibet Plateau is the main production area of winter worm summer grass. Qinghai Province accounts for over 70% of the total production, followed by Tibet and Sichuan. Additionally, Gansu and Yunnan also have distribution of winter worm summer grass, albeit in smaller quantities.
Growth of Winter worm summer grass
Every year, starting in August during the peak of summer, bat moths lay thousands of eggs on the flowers and leaves of high-land plants. These eggs hatch into larvae, which burrow into moist and loose soil, absorbing nutrients from the roots and stems of plants. If they happen to come across mature Cordyceps fungal spores that have fallen into the soil, the spherical spores of the Cordyceps fungus penetrate the larvae’s bodies, absorbing their nutrients and germinating hyphae. The infected bat moth larvae become sluggish in their movements. Around October, when the environmental temperature is between 2-9°C, the infected larvae gradually crawl to a depth of two to three centimeters below the surface and die with their heads down. This is the “winter worm”.
At this point, although the bat moth larvae have died, the fungus inside their bodies continues to grow. From November to February of the following year, when the surface temperature is extremely low, the growth of the Cordyceps fungus inside the dead bat moth larvae slows down or even stops. By May, when the temperature rises to 4-10°C and the soil thaws, the fungus resumes its growth, completely filling the entire larval body. It then forms a layer of mycelium that adheres to the soil, followed by the emergence of a purple-red, pineapple-shaped fruiting body, approximately 2-5 centimeters long, from the head of the dead larva. This is the “summer grass”.
The spores use the larval body as a nutrient source and grow rapidly. The larval body typically reaches a length of four to five centimeters, and the spores can grow to the same length as the larval body within a day. At this stage, the Cordyceps is fully developed and contains the highest concentration of active ingredients. This is known as “head grass” and is of the highest quality. The next day, the spores grow to about twice the length of the larval body, known as “second grass”, and the quality is slightly lower.
By the middle to late July, the head of the cylindrical fruiting body gradually enlarges, and the ascospores mature and are ejected under suitable temperature, humidity, and light conditions. At this point, the underground insect decays, and the fruiting body becomes hollow. The released spores are dispersed by wind and water to infect the larvae of bat moths, starting the next cycle of Cordyceps growth.
In its natural state, it takes approximately three years for Cordyceps to complete its asexual and sexual generations.
Bat Moths and Cordyceps Fungus
For bat moths, Cordyceps fungus is like a “ghostly phantom” that takes over their bodies and consumes them. However, the beauty of nature lies in the fact that what appears to be an “invasion” is actually a perfectly balanced cooperation.
Cordyceps fungus infects bat moth larvae in a controlled manner, with an infection rate of approximately 12% in the natural distribution area of Cordyceps. This means that the majority of bat moth larvae can still continue to reproduce. Scientists are currently unclear about the specific mechanism of this infection.
Furthermore, without the infection of Cordyceps fungus, it may not necessarily be beneficial for bat moths. The bat moths, mainly found in the alpine meadows of the Qinghai-Tibet Plateau, primarily feed on the root buds of plants in the Polygonaceae and Poaceae families, occasionally consuming a small amount of tender roots of woody plants. If they have no natural predators, the larvae will multiply rapidly and quickly deplete their food sources, leading to the inability of bat moths to survive. Therefore, there exists a sustainable balance between Cordyceps fungus and bat moths, as well as between bat moths and alpine meadow plants.
Interestingly, the alpine bat moth, found only in the Qinghai-Tibet Plateau, is the exclusive host insect for Cordyceps fungus. Unlike other fungi in the same family, which can use a variety of different insect populations as hosts, Cordyceps fungus specifically relies on the alpine bat moth.
Currently, the majority of known bat moth species in China are distributed in the Qinghai-Tibet Plateau, with 6 genera and 46 species in total. Among them, 37 species can serve as hosts for Cordyceps fungus. These insects’ distribution centers coincide with the main production areas of Cordyceps fungus.
Morphology of Winter worm summer grass
Cordyceps sinensis consists of a “insect body” connected to a “grass (ascocarp)”. It is approximately 7-15 centimeters in length, with the following characteristics:
The “insect body” is about 3-5 centimeters long and 0.3-0.8 centimeters in diameter. It has a deep yellow to yellow-brown color, with rough and distinct rings. There are 20-30 rings, with the rings near the head being finer. The head is reddish-brown, appearing dark yellow or yellow-brown on the surface. There are 8 pairs of legs, with 3 pairs near the head, 4 pairs in the middle, and 1 pair at the tail. The texture is brittle and easily breaks, with a slightly flat, pale yellow-white section.
The “grass (ascocarp)” grows from the head of the insect body, appearing slender and cylindrical. The base covers the head of the insect body, forming a long rod-shaped structure. It is 4-8 centimeters long and approximately 0.3 centimeters in diameter. The surface is dark brown to brownish-brown, with fine longitudinal wrinkles. The upper part is slightly swollen, and there is no clear distinction between the head and the stalk. The texture is soft and flexible, and the cross-section is mostly white and hollow. It has a slight fishy smell and a slightly bitter taste. It has a mushroom-like fragrance when smelled.
The “perithecium (enclosing fungal spores)” is mostly embedded in the “ascocarp”, with the tip protruding from the “ascocarp”. It is oval or elliptical, measuring 250-500 micrometers in length and 80-200 micrometers in diameter. Each perithecium contains several elongated linear asci, and each ascus contains 8 ascospores with septa. The host is the larvae of Lepidoptera and Coleoptera insects. In winter, the fungal mycelium invades the larvae hibernating in the soil, causing the larvae to be filled with mycelium and die. The ascocarps grow in the summer.
Cordyceps sinensis with a bright yellow color, plump and large size, and a yellow-white cross-section is considered the best.
Cordyceps sinensis has distinct patterns, while the legs of other Cordyceps species are not as prominent.
Harvesting and Preservation
The season for harvesting Cordyceps sinensis is around the summer solstice (May-June), when the snow has not completely melted. At this time, the “grass (ascocarp)” of the Cordyceps can be found protruding from the snow, not exceeding one inch. If it is too late, the snow will melt, weeds will grow, and it will be difficult to find. Additionally, the larvae in the soil will wither and will not be suitable for medicinal use.
According to experienced locals in the production areas, when searching for Cordyceps, one must bend down or crawl on the ground to carefully observe (easier to find in the morning, difficult at noon). Once one Cordyceps is found, there are likely others nearby. In the densest areas, 10 to 20 Cordyceps can be found in one square meter. Digging Cordyceps is a meticulous and patient task, and it is best to use tools such as small iron rods or wooden sticks to excavate them. The distance from the mycelium should be about one inch. Digging too close or too far may break the larva, so it is not advisable to directly pull and excavate by hand.
After digging, remove the outer layer of soil and membrane while the larva is still moist. Dry it in the sun, straighten it out, and tie 6 to 8 pieces together with a red thread. Use low heat to dry them.
Storing Cordyceps in a well-ventilated environment will prevent spoilage and mold. If it is too humid, it can be sealed in a bag and stored in the refrigerator.
Main Components of Cordyceps
According to modern pharmacological research, Cordyceps sinensis from Qinghai contains approximately 7% cordycepin, 28.9% carbohydrates, 8.4% fat, 25% protein, and 82.2% of the fat is unsaturated fatty acids. In addition, it also contains vitamin B12, ergosterol, hexose alcohol, alkaloids, etc.
Other components include cordycepic acid, cordycepin, amino acids, sterols, mannitol (adenosine), alkaloids, vitamins B1, B2, polysaccharides, and minerals.
The main components of Cordyceps mentioned above are still subject to doubt and controversy. It has been found that “cordycepin” does not exist in Cordyceps.
Medicinal Records
In China, Cordyceps sinensis is considered one of the top three tonics, alongside ginseng and deer antler. It is also recorded in the ancient Tibetan medical book “Yue Wang Yao Zhen” (Precious Medicine of the Moon King).
It was not until 1757, in the personal work “Ben Cao Cong Xin” by Wu Yiluo, a folk doctor in the Qing Dynasty, that Cordyceps sinensis was included. The book describes Cordyceps sinensis as having a sweet and warm nature. It is believed to tonify the lungs and kidneys, transform phlegm, and stop coughing. It can be used for chronic cough, asthma, postpartum weakness, impotence, and coldness caused by “deficiency” conditions.
The book “Ben Cao Gang Mu Shi Yi” provides detailed information: “Summer grass, winter worm, found in Hualinping, Jiangyou County, Sichuan. It appears as grass in summer and transforms into a worm in winter. It is about three inches long with six legs below. It is different from ordinary silkworms and is highly valued by the Qiang people as a superior medicine.”
It also quotes from the book “Qi Chun Yuan Xi Yu Wen Jian Lu”: “Summer grass and winter worm grow in the snowy mountains. In summer, it looks like a leafy leek, and its roots resemble rotten wood. In the severe winter, the leaves dry up, and the roots transform into worms.”
Another quote from “Liu Ya Wai Bian” states: “Winter worm, summer grass, is the same thing. In winter, it is a worm, and in summer, it becomes grass. The worm resembles a silkworm and is slightly yellow in color, while the grass resembles leek with thinner leaves.”
Based on the descriptions of its morphology in the above literature, as well as the recorded origin and habitat, and with reference to the illustrations in “Zhi Wu Ming Shi Tu Kao” (Illustrated Examination of Plant Names and Realities), it can be determined that the Cordyceps sinensis fungus of the Ophiocordyceps genus and its parasitic complex is the traditional medicinal Cordyceps sinensis.
However, “Ben Cao Gang Mu Shi Yi” also states: “According to ‘Sichuan Tong Zhi’, winter worm and summer grass are found in Litang Bolanggong Mountain. They have a warm nature and tonify essence and marrow.” According to the “New Edition of Chinese Materia Medica”, the “winter worm and summer grass” mentioned here refers to Cordyceps liangshanensis Zang, Hu et Liu, a substitute for Cordyceps sinensis used in western Sichuan and northeastern Yunnan. This indicates that there may have been a case of using different substances with the same name for Cordyceps sinensis in ancient times.
Furthermore, according to the records in the “Pharmacopoeia of the People’s Republic of China”, Cordyceps sinensis is commonly used to treat tuberculosis, asthma, bronchitis, and emphysema.
Function and Benefits
The reason why Cordyceps sinensis is so highly regarded is not only because of its unique way of existence, but also because of the attributed benefits.
It has expectorant and anti-asthmatic effects, with significant dilation effects on bronchial smooth muscle and the ability to enhance the action of adrenaline. It can improve the kidney function and enhance cellular immune function in patients with renal failure, and it is effective in experimental nephritis.
In addition, many people believe that Cordyceps sinensis has anti-tumor effects because it was previously believed to contain a large amount of cordycepin, which has anti-cancer and antibacterial activity.
However, researchers from the Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, have recently confirmed that there are no genes for cordycepin synthesis in Cordyceps sinensis. In fact, the active substance responsible for the treatment of various diseases by Cordyceps sinensis is still unknown. Whether Cordyceps sinensis can treat or assist in the treatment of diseases is also unknown.
However, the recorded benefits in the pharmacopoeia, as well as the folk use of Cordyceps sinensis to enhance immunity, especially in accelerating postoperative recovery, are currently acknowledged in clinical practice. It is just that the specific components of Cordyceps sinensis corresponding to various benefits have not been definitively identified in medical research.
Controversy over Efficacy
There has been ongoing debate among professionals regarding the presence of effective components in Cordyceps sinensis.
Initially, cordycepic acid was believed to be the active ingredient or signature component of Cordyceps sinensis. However, it was soon discovered by the academic community that cordycepic acid is actually mannitol, a very common and inexpensive chemical product widely used in food and medicine.
Subsequently, Cordyceps sinensis was promoted as containing cordycepin, a rare adenosine-like active substance that may have anti-cancer effects. In 2017, the latest research results from the “Wang Chengshu Team” at the Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, were published in “Cell Chemical Biology”, a subsidiary journal of the internationally renowned scientific journal “Cell”. The research revealed that Cordyceps sinensis does not contain pentostatin, an anti-cancer compound, or cordycepin produced by its biosynthesis.
The study also pointed out that excessive levels of cordycepin can cause cellular toxicity in fungi, which means that excessive intake of cordycepin is not suitable for humans.
On February 4th, 2016, the China Food and Drug Administration issued a “Consumer Alert on Cordyceps Sinensis Products”, stating that the tested Cordyceps sinensis, Cordyceps sinensis powder, and pure powder tablet products contained arsenic levels ranging from 4.4 to 9.9 mg/kg, posing a high risk. As a result, in 2016, the China Food and Drug Administration removed Cordyceps sinensis from the category of health food, and the declaration and approval of health food containing Cordyceps sinensis were regulated according to the “Administrative Measures for the Registration and Filing of Health Food”. Furthermore, the “Notice on Stopping the Pilot Use of Cordyceps Sinensis in Health Food” explicitly stated that Cordyceps sinensis is not a dual-use substance for medicine and food, and it cannot be used as a raw material for ordinary food production and sales without approval.
On May 30th, 2018, it was reported that the former China Food and Drug Administration (CFDA) reiterated that Cordyceps sinensis is not a health product.
Classification of Winter worm summer grass
According to research, there are multiple species of Cordyceps fungi in China, but only one species, Cordyceps sinensis, is recognized as a medicinal material and included in the Chinese Pharmacopoeia. It is important to note that only Cordyceps sinensis is considered authentic Cordyceps.
The Cordyceps fungus has over 30 species of host insects in the genus Bat Moth. Therefore, the Cordyceps sinensis produced in different regions may vary in length, thickness, shape, and composition due to differences in the insect species, growth environment, types of plants, and their quality.
Apart from Cordyceps sinensis, there are many other organisms that can be classified under the “Cordyceps” genus. Some of these are recorded in traditional Chinese medicine literature, including Cordyceps hawkesii, Cordyceps militaris, Cordyceps liangshanensis, and Cordyceps ophioglossoides, among many others. In a broader sense, there are currently reports of around 400 different species of Cordyceps. However, in terms of price, Cordyceps sinensis is several times higher or even more than ten times higher than these other Cordyceps species.
In terms of origin, authentic Cordyceps sinensis from completely wild sources is classified by professionals as Qinghai Cordyceps (produced within Qinghai Province), Zangcao (some refer to it as produced within the Tibet Autonomous Region), Chuancao (produced within Sichuan Province), Diancao (produced within Yunnan Province), Gansucao (produced within Gansu Province), and so on.
Authentic Cordyceps sinensis can be further classified into two types based on their growth environment: grassland Cordyceps from high-altitude grasslands and mountain Cordyceps from high-altitude shady mountain valleys. Due to differences in the growth environment and soil quality, they exhibit slight variations in color and morphology.
Grassland Cordyceps is a yellowish color with a plump and soft texture.
Mountain Cordyceps is dark brown with a full and solid body.
Conservation of Winter worm summer grass
Cordyceps sinensis was classified as a second-level protected species in China in 1999.
On July 9, 2020, the International Union for Conservation of Nature (IUCN) listed Cordyceps sinensis in the Redlist of China’s Biodiversity – Macrofungi, with a conservation status of Vulnerable (VU). The IUCN website can be found at https://www.iucn.org/.
The main factors contributing to the decline in population numbers are global climate change and over harvesting.
Reasons for Vulnerability
Due to the impact of global climate change, the snow line on the entire Qinghai-Tibet Plateau has been rising, leading to significant changes in the distribution pattern of Cordyceps sinensis in the cold alpine meadows of the plateau.
Known as the “Asian Water Tower,” the Qinghai-Tibet Plateau is home to the core distribution zone of Cordyceps sinensis, situated in the high-altitude meadows at the headwaters of major rivers such as the Yangtze River, Yellow River, Lancang River, Yarlung Zangbo River, Nu River, and Yalong River. Its ecological significance extends beyond Asia to the entire globe.
Currently, the core distribution zone within the main production areas of Cordyceps sinensis has noticeably shrunk. Approximately 30 years ago, the altitude range for the growth of Cordyceps sinensis was between 3800 and 4500 meters. However, the current core distribution area has shifted to an altitude range of 4400 to 4700 meters.
The population of Cordyceps sinensis in the altitude zone of 4200 to 4500 meters, where it used to be concentrated, has been decreasing year by year. In some areas, Cordyceps sinensis has not been found for many years, and host insects are no longer present.
Driven by immense profits, “gold diggers” have been relentlessly collecting this species, causing the degradation of the grassland ecosystem and a continuous decline in the population of Cordyceps sinensis.
Currently, the harvesting area of Cordyceps sinensis in the entire Qinghai-Tibet Plateau has expanded by 5 to 6 times, but the overall yield remains similar to the past. In other words, the yield per unit area has significantly decreased.
Even in areas where Cordyceps sinensis used to grow most densely, scientists have found very few Cordyceps sinensis specimens and host insects during their collections.
