Why are little earthworms valued so much?
One of the oldest species in the world
Earthworms are regarded as one of the fundamental organisms in the world. As early as 1837, biologist Darwin called earthworms “the most valuable animals on earth.”
A large number of studies have determined that earthworms are one of the oldest species in the world, originating about 570 million years ago, which is even older than dinosaurs in the Jurassic era (about 200 million years ago).
The body of earthworms is slender, symmetrical on both sides, composed of many segments, and each segment is very similar in shape. They have no bones and are covered with a thin, pigmented cuticle. After the 11 somites, there are dorsal holes on the dorsal line of each segment, which can discharge body cavity fluid, moisten the body surface, and facilitate breathing and walking through the soil. Earthworms have no legs, but they can move. They move forward through muscle contraction and the cooperation of setae.
At present, there are more than 3,000 kinds of earthworms known in the world. The general body length is about 6 to 12 centimeters, the weight is about 0.7 to 4 grams, and the heaviest is 1.5 kilograms. It is composed of segments, the front part is slightly pointed, the rear end is slightly rounded, and there is an indistinct ring at the front end.
However, there is a Gippsland giant earthworm living in Australia, which can reach a length of 3 meters, showing the “kingdom” of earthworms. This kind of earthworm is distributed in the Mornington Peninsula. It is not only large in size, but also has a beautiful complexion, which is quite like a peacock spreading its tail. It has a dark purple front and pink and gray back. As the king of earthworms, the Gippsland giant earthworm lives in deep underground caves, and it is difficult for people to see its true colors. It is also a unique native animal that only exists in Australia and is an endangered species.
There is also a huge “caecilian” in the forests of South America, which means a giant earthworm. It is named for its resemblance to an earthworm. But in fact, this caecilian is far from the biological relatives of earthworms. It belongs to amphibians and vertebrates. It is said that this caecilian can be more than 2 meters long, longer than the average snake.
According to the Guinness Book of World Records, there is a giant earthworm as long as 6 meters in southern Africa, but very few people have seen it. The largest earthworm in my country has appeared in Sichuan. It is about 78.7 cm long and 2.5 cm thick. It is said that it can survive for 20 years.
Earthworms live underground for many years, so they avoid strong light and prefer weak light. Unlike most animals, earthworms are hermaphrodites, but require crossbreeding for fertilization. Under the right conditions, mature earthworms can reproduce once a month. The eggs just laid by earthworms are transparent, oval or spindle-shaped, milky yellow at first, then turn red in about 7 days, and then hatch into small earthworms in about 7 days.
The lifespan of various earthworms is not the same, and some are quite different. The lifespan of the genus Cylindrica is mostly one year, such as the common Cylinophora and Xizhen Cylindricus. The lifespan of Heteroderma heterochaetoides, Heterocystis hubeiensis, and giant annulus is more than one year. They survive the winter as adults and lay eggs in the spring of the following year. The earthworms of the genus Heterophyllum and Orthorum genus have a longer lifespan. Essium chrysalis can survive for more than 4 years, Earthworm terrestrialis can survive for up to 6 years, and Earthworm Esophagus can survive for 5 to 10 years under good feeding conditions in the laboratory.
The real “earth dragon”
Many ancient mythological works in our country have fictionalized the creature “dragon”, which lives in the sea, water and sky. In fact, there are also “dragons” under the earth, and they are real. They are “earth dragons” – earthworms.
In myths and legends, there are different dragons in different sea areas, such as the Dragon King of the East China Sea and the Dragon King of the North Sea. In real life, there are different earth dragons in different regions. In Guangdong, Guangxi, and Fujian, the “Guangdi Dragon” is the king; in Shanghai, Zhejiang, and Jiangsu, the “Shanghai Dragon” is the king; and in other places, the “Land Dragon” is the king.
In fact, Earthworm is just a good name for earthworms. There are many names for earthworms, such as duck insects, Yinwu, Quexing, Hanxin, Mingji, Huanggou, Quzhi, and Dilongzi. Although each nickname for earthworms has a corresponding rationale, such as “duck worm” refers to a favorite food of birds, and “song worm” refers to insects like crickets and field eels.
The reputation of Earth Dragon has a long history in our country. It has medical reasons, biological factors, and folk legends.
The earliest traditional Chinese medicine book “Shen Nong’s Materia Medica” records that the original name of earthworms is earthworms, which is one of 46 kinds of animal medicines. In Li Shizhen’s “Compendium of Materia Medica”, earthworms began to be called earthworms, which is also a common name, and they are believed to have the functions of clearing away heat, calming wind, relieving asthma, dredging collaterals, and diuresis.
From a biological point of view, earthworms are not named just because earthworms have medicinal value and are distinguished according to the place of origin, because some of them are huge in shape, even surpassing ordinary snakes, so the ancients called them “earthworms”. Dragon” is not an exaggeration.
The name of Earth Dragon is widely spread in Chinese folklore. According to legend, Song Taizu Zhao Kuangyin suffered from herpes zoster when he first came to the throne. This is an acute inflammatory disease caused by varicella zoster virus. Traditional Chinese medicine calls this disease “waist-wrapped dragon”, “waist-wrapped fire dragon” and “snake pan sore”. Chickenpox occurs at the first infection, which is unbearably painful. Zhao Kuangyin was restless and didn’t think about eating or drinking. The medical officer of the Tai Hospital tried all methods to no avail. Seeing that he was about to be punished by the emperor, in desperation, the medical officer had no choice but to recommend a pharmacy shopkeeper who was good at treating skin diseases into the palace. The shopkeeper diagnosed Zhao Kuangyin as suffering from “waist-wrapped dragon”. He opened the medicine jar, took out a few earthworms and put them on two plates, sprinkled honey bee sugar to dissolve it into water, and then dipped cotton in it and applied it on the affected part of the emperor’s waist. , Zhao Kuangyin immediately felt cool and comfortable, and the pain relieved a lot. Afterwards, he brought another plate of earthworm juice and asked Zhao Kuangyin to take it orally. Zhao Kuangyin asked: “What kind of medicine is this? It can be taken internally or used externally?” It will work.” Zhao Kuangyin was overjoyed after hearing this, and took it immediately. After a few days, the herpes subsided and the pain disappeared. Since then, the name of Dilong has spread.
Ecosystem “engineers”
It’s hard to imagine that a naked earthworm can make a sound. The ancients discovered this phenomenon very early. According to Ouyang Xiu’s “Miscellaneous Comments” records: “Earthworms eat soil and drink springs. They live, and they are simple and easy to foot. Then they look up at their holes and sing, as if they are called.” There are also folk songs: earthworms cry at night and rain, The sky is sunny when the spider spreads its web. It is even mentioned in “Compendium of Materia Medica” that earthworms “begin to emerge in summer, stagnate in midwinter, come out first when it rains, and sing at night when it is sunny.”
But from an anatomical point of view, earthworms do not have any vocal organs in their bodies, so they cannot sing. Scientists speculate that people may hear earthworms singing because of the vibration of their internal diaphragms, or the sound of food wriggling and rubbing in their digestive tracts, or the sound of bristles rubbing against soil when earthworms crawl in the soil. It’s the sound of an earthworm venting.
Affected by Darwin’s research results in “The Production of Humus and the Function of Earthworms”, scientists now study the behavior of earthworms drilling around in the soil. In the field of biology, there is a professional term, that is, soil bioturbation. Bioturbation is a general term, which refers to the sedimentary structure formed by the reprocessing of sediment by animals and plants, including burrowing, ingestion and defecation of sediment particles.
Earthworms live in moist, loose soil all year round and are omnivores. Most earthworms can eat their own body weight in food every day, and they swallow a lot of food every day, and then excrete feces. Therefore, the excrement of earthworms is rich in humic acid, fulvic acid and microbial flora, which can effectively improve the fertility of the soil, make the soil loose and fertile, and benefit the growth of crops. This means that the important role of earthworms is to fertilize and protect the soil, as well as to maintain ecological balance and maintain biodiversity. It has long been a consensus among people that there is fertile soil where there are earthworms, so earthworms are the “nutrition husband” of the land.
”Nutrition husband” is just one recognized role of earthworms, and the other is “soil cleaner”. Earthworms are effective at decomposing waste organic matter because they have a well-developed digestive system and are able to feed on soil and organic waste. The fermented organic waste can be rapidly decomposed and transformed by the action of protease, lipolytic enzyme, chitinase, cellulase and amylase in the digestive system of earthworms. Earthworms also have the characteristics of wide feeding habits and large food intake, so they can deal with various urban wastes, especially industrial wastes produced by clothing, food processing, and slaughterhouses. After the application of heavy metal pesticides, the residual amount in the soil is relatively high, and the earthworms inhabiting the soil can absorb and enrich the residual pesticides, especially the small earthworms located on the soil surface are more effective than the large earthworms located in the deep layer.
In addition, earthworms are also “cleaners” in a broad sense. Vermicompost has high porosity, large surface area and fairly strong deodorization ability, which can absorb harmful and odorous gases in the environment. Vermicompost also contains a variety of microbial flora such as filamentous bacteria, actinomycetes, and Escherichia coli. These flora absorb sulfur dioxide, hydrogen sulfide, mercaptans and other malodorous gases, which can be quickly decomposed into odorless gases, thereby improving air pollution. . Therefore, vermicompost can be used as a natural gas deodorizer.
Generally speaking, earthworms are genuine ecosystem “engineers” regardless of their ugly appearance. They dredge the land and move the soil. A healthy earthworm population can move more than 3 tons of soil per mu of land in one year . The feces excreted by earthworms have complete nutrients, remarkable fertilizer efficiency, good air permeability and moisture retention, and are called “the king of organic fertilizers”.
Generally speaking, earthworms are genuine ecosystem “engineers” regardless of their ugly appearance. They dredge the land and move the soil. A healthy earthworm population can move more than 3 tons of soil per mu of land in one year . The feces excreted by earthworms have complete nutrients, remarkable fertilizer efficiency, good air permeability and moisture retention, and are called “the king of organic fertilizers”.
Today, one of the criteria for judging whether a piece of land is fertile is how many earthworms per unit area of the land. When the number of earthworms per square meter of soil is greater than 50, it means the soil is in a healthy state; when the number is 20 to 50, it means that the soil is in a moderately degraded state; when the number is 4 to 20, it means that the soil is in a severely degraded state; If it is less than 4, it means that the soil is in an extremely unhealthy compaction state. Land with more earthworms can become a productive field after 3 years. There are 1 million earthworms in each mu of garden soil, which is equivalent to 3 skilled workers working in rotation for 8 hours a day, and 10 tons of fertilizers are applied to the soil every year. Therefore, in relatively fertile land, the density of earthworms can reach 1 million to 2 million per mu.
Therefore, Darwin once commented on earthworms and said: “It is difficult for us to find other creatures like them. Although they seem humble, they have played such an important role in the process of world history.”
The whole body is precious and has wide medicinal value
Earthworms live in the dark underground, but have never been attacked by diseases; earthworms have super regeneration ability, even if they are broken in two, they can survive; the internal environment of earthworms is very stable, ensuring that genes will not mutate rapidly. All these indicate that earthworms have strong immune function, strong detoxification function and stem cell regeneration ability.
Studies have shown that the protein content in earthworms reaches 70%, and also contains many trace elements, such as phosphorus, calcium, iron and so on. Its function lies in its medical value, that is, various substances in its body have the effect of curing diseases and keeping fit.
All kinds of earthworms contain earthworm pyrolytic alkali, vermisin and lumbrokinase. In addition, “Guangdilong” contains 6-hydroxypurine, succinic acid and glutamic acid. Earthworms also contain xanthine, adenine, guanine, choline, and guanidine, as well as various amino acids, such as alanine, valine, and leucine, which are the basic units of various proteins.
In 1982, Japanese researchers discovered urokinase-like proteases in the intestines and body fluids of earthworms. In 1984, Chinese researchers isolated and purified fibrinolytic enzyme, namely lumbrokinase, from artificially raised earthworms, which can directly degrade fibrin in the blood and activate plasminogen into plasmin under physiological conditions to accelerate thrombus. of the dissolution. Since then, more studies have proved that lumbrokinase has good clinical application value, can effectively dissolve microthrombosis, improve microcirculation, increase blood vessel elasticity, and inhibit thrombus formation again. Therefore, lumbrokinase is widely used clinically to treat cardiovascular and cerebrovascular diseases, such as stroke, thrombolysis, and the prevention and treatment of endocrine and respiratory diseases. It can even be used for thrombolysis of snakebite, such as snakebite hurt. Nowadays, drugs using earthworm and lumbrokinase are very popular in the market, and have even become basic drugs for cardiovascular and cerebrovascular diseases.
Because of its extensive medicinal value, the demand for earthworms in the market continues to increase. According to the data of Chinese medicinal earthworms, in 2010, the demand for earthworms reached 400 tons, and by 2020, the demand will increase to 675 tons. With the increase in demand, the price of earthworms in the market has also increased significantly in recent years.
So, someone came up with the “trick” of using electricity to catch wild earthworms. This electric capture method will cause a devastating blow to earthworms in the entire electric shock range, so the electric capture method is also called “extinct” capture.
In 2020, the China Biodiversity Conservation and Green Development Foundation submitted a complaint to the Intermediate People’s Court of Zhuhai City, Guangdong Province, and filed a public interest lawsuit against three home appliance earthworm machine manufacturers in Zhongshan, Guangdong Province. In legal circles, this case is known as “the first case against electric earthworms”. In the end, the court ruled that the three defendants should pay 1.59 million yuan in compensation for their violations of the ecological environment.
So far, Beijing, Guangdong and other places have introduced regulations to include wild earthworms in the scope of protection. This year’s No. 1 Central Document explicitly prohibits soil-destroying behaviors such as electric trapping of earthworms, which is a strong commitment to green, circular, and low-carbon development methods.
