Q: The habits of silkworms

Scientific name: BombyxmoriLinnaeus

Alias: BombyxmoriL. ), referred to as silkworm.

Insecta, Lepidoptera, Bombycidae.

One of the economic insects that feed on mulberry leaves and cocoon. Silkworm originated in China. As early as four or five thousand years ago, our ancestors planted mulberry and sericulture, which is recognized as one of the great inventions in the world. Domesticated from primitive silkworms that lived on mulberry trees in ancient times, they are homologous to wild silkworms that eat mulberry trees in China today, and both have 28 pairs of chromosomes. The development temperature of silkworm is 7-40℃, and the optimum feeding temperature is 20-30℃, which is mainly distributed in temperate, subtropical and tropical regions. Silkworm is a completely morphological insect, which has to go through four completely different developmental stages: egg, larva, pupa and adult. Eggs are the stage of embryogenesis and development to form larvae, larvae are the growth stage of feeding, pupae are the metamorphosis stage of the transition from larvae to adults, and adults are the reproductive stage of mating and spawning to reproduce offspring. The whole generation only eats in the larval stage, storing nutrients for the life activities of pupae and adults. Silkworm Origin Editor: Silkworm originated in China. Domesticated from primitive silkworms that lived on mulberry trees in ancient times, the morphology and habits are very similar to those of wild silkworms (Bombyxmandarina) that eat mulberry leaves today (see mulberry pests), and the serum precipitation reaction intensity is also the same, and normal offspring can be produced by hybridization. Silkworm has 28 pairs of chromosomes, while wild silkworm has 27 pairs and 28 pairs. It is generally believed that silkworm is homologous to 28 pairs of wild silkworm in China. At first, humans may have collected primitive wild cocoons from mulberry forests for silk utilization; With the settlement of human life and the further understanding of the use of silk, sericulture began to try indoors. After long-term cultivation and selection, wild silkworm has gradually domesticated into a silkworm variety with today's economic characteristics. Silkworm's living habits Silkworm is an oligophagous insect. It likes to eat not only mulberry leaves, but also mulberry leaves, elm leaves, crow onions, dandelions and lettuce leaves. The essential nutrients of silkworm include protein, carbohydrates, lipids, vitamins, inorganic salts and water. Mulberry leaves are the most suitable natural food for silkworms. After eating mulberry, the larvae grow rapidly. Under suitable temperature conditions, a silkworm molts once every 6-9 days, which takes about 24-32 days, and eats 20-30 grams of mulberry leaves (5-6.2 grams of dry matter). Generally, after four times of sleep and molting, its weight increases to the extreme about 65438+ 100000 times. Spinning cocoon is an instinct for silkworm to adapt to the environment. Mulberry cocoon can be reeled, and silk is a precious textile raw material, which is also widely used in military industry and electric power. Silkworm pupa, silkworm moth and silkworm excrement can also be comprehensively utilized, which are raw materials for various chemical and pharmaceutical industries and can also be used as nutrients for plants. Silkworm is a completely metamorphosed insect, which has experienced four development stages: egg, larva, pupa and adult. The naturally occurring generations in a year are called homogenization, one year 1 generation, two generations are dual, and more than three generations are pluralism. In the tropics, there are also diversified varieties that do not diapause all year round. The temperature range of development varies with different developmental stages, which is roughly between 7℃ and 40℃, and the temperature range of normal development is between 20℃ and 30℃. Silkworm larva

Long cylindrical, consisting of head, chest and abdomen. The head is covered with taupe bones, and the chest has 1 pair of chest and feet in each of the three links; There are 4 pairs of abdominal feet and 65,438+0 pairs of tail feet in the 65,438+00 links of the abdomen, and there are 65,438+0 tail angles in the center of the back of the eighth abdominal segment. 1 thoracic segment and 1 to the 8th abdominal segment, there are 1 pairs of valves on the body side. The newly hatched larvae are covered with dark brown bristles as small as ants, and are called ant silkworms. Ant silkworm feeds on mulberry leaves and grows rapidly, and its body color gradually turns blue and white. The epidermis of its body wall will fall off many times, which is called molting, which is the result of the joint action of juvenile hormone secreted by silkworm pharynx and molting hormone secreted by thymus gland. Before molting, the larvae stop eating mulberry, spin silk on the silkworm bed, and fix the silkworm body with its abdomen and tail feet, which is called sleep. Sleep is the boundary of age division, and each sleep increases 1 age. Weight and volume increase significantly with age. The characteristic of molting times is called sleepiness, which is controlled by heredity, but the influence of living conditions will also change sleepiness. Silkworm sleep has three sleeps, four sleeps and five sleeps. The commonly used silkworm variety in production is the four-sided five-year-old silkworm. Larvae can be distinguished according to their characteristics when they reach the 2nd to 3rd day of 5th instar: female silkworms have 1 ivory dots on the ventral surface of the 8th and 9th ventral nodes, which are called Duchenne glands; The male silkworm has a milky white cystic body in the center of the ventral front edge of the ninth abdominal segment, which is called Hertzian gland (Figure 2). When the 5th instar reaches its peak, its weight is about 654.38+00000 times that of the ant silkworm. After that, gradually reduce the amount of mulberry and even stop eating. When the front half is transparent, it is called a mature silkworm, that is, it begins to spin silk and form cocoons. The cocoon forming process takes about 2 ~ 3 days. The length of larval stage varies with silkworm species and feeding conditions. Generally, it takes 24 ~ 26 days for spring silkworm at 24 ~ 25℃, and 265,438+0 ~ 23 days for summer and autumn silkworm at 26 ~ 28℃.

pupa

After the mature silkworm spins silk, its body shrinks slightly into a spindle shape and stands still. At this time, it is called latent pupa (pre-pupa). Latent pupa is the period when the dermis and epidermis of old larvae are separated and the pupa epidermis is formed, which takes about 2 days. Pupation and molting are the results of molting hormone. The newly molted pupa is spindle-shaped, milky white, and then turns dark brown. The pupa's body is divided into three parts: the chest and the abdomen. The female pupa has a large abdomen and a blunt end, and there are 1 longitudinal lines on the ventral midline of the eighth abdominal segment. The abdomen of male pupae is small and sharp, and there is a 1 brown spot in the center of the ventral surface of the 9th abdominal segment (Figure 3). Generally, the pupa weight 1.5 ~ 2.5g ... In the pupa stage, the destruction of larval tissues and organs, the occurrence and formation of adult tissues and organs, and the development and maturation of germ cells are all intense. Adult development is completed about 14 days after pupation. At this time, the eclosion hormone synthesized by brain nerve secretory cells and stored in the pharynx is secreted into the blood due to the stimulation of light, and the pupa will eclosion after about 40 minutes. Adult (moth)

After eclosion, the adults spit out alkaline intestinal juice to moisten and loosen the cocoon layer at the head end, and push the cocoon silk with their chests and feet to get out of the cocoon. Wings are soft and folded at first, and spread out when the moth's body dries. The whole body is covered with white scales, and there are 1 pairs of compound eyes and 1 pairs of comb-shaped antennae with touch and smell on both sides of the head, and the mouthparts have degenerated. There are 1 pairs of pectoral feet on the ventral surface of the anterior, middle and posterior thoracic segments, and 1 pairs of wings on the dorsal surface of the middle and posterior thoracic segments. There are 7 female moths and 8 male moths in the abdomen. The external genitalia of the male moth began to change from the 9th and 10 abdominal nodes of the larva, and the external genitalia of the female moth began to change from the 8th, 9th and 10 abdominal nodes. During mating, the female moth extends out of the ovipositor, and the sex pheromones (silkworm alcohol and silkworm aldehyde) released by the attracting gland attract the male moth, and the fertilized egg can be produced after mating 1.5 ~ 2 hours. A female moth lays about 400 ~ 700 eggs, most of which lay eggs on the day of emergence and end on the third day. Adults do not eat, mate and lay eggs 10 days or so and die naturally. egg

The ellipse is slightly flat, about 1. 1 ~ 1.5 mm long, about 1.0 ~ 1.2 mm wide and about 0.5 ~ 0.6 mm thick. One end is slightly blunt, the other end is slightly sharp, and there is an egg hole at the top, which is a fertilization channel. The size of eggs varies with silkworm species, feeding conditions and pupa temperature. The weight of eggs is generally 500 ~ 600 micrograms. When I was born, it was pale yellow with a raised surface. Later, due to the evaporation of water and the consumption of nutrients in the egg, the center of the egg surface appears concave, which is called egg vortex. The egg vortex of normal eggs is oval, and the dead eggs are triangular. There are uneven polygonal egg lines and numerous needle-like breathing holes on the surface of eggshells. The contents of an egg include yolk membrane, serosa, yolk and embryo. The yolk membrane is close to the bottom of eggshell and is a cell-free transparent membrane. On the inside, the serosa is a large and flat polygonal cell. Egg yolk is a source of nutrition for embryonic development. Embryo is located on the side of the egg in the yolk, with its head facing one end of the egg hole, and gradually develops through continuous absorption of nutrients. Silkworm eggs are divided into diapause eggs (over-age eggs) and non-diapause eggs (under-age eggs). After the non-diapause eggs are laid, the embryos continue to develop, and the ants hatch in about 10 days. Diapause eggs develop to a certain extent and enter diapause, which is released at low temperature in winter and hatched in the following spring. Whether silkworm eggs diapause depends on whether the hypopharyngeal ganglion of female pupae can secrete diapause hormone; Cardiac hormone also plays an auxiliary role in diapause. Diapause eggs enter the diapause stage, and pigment particles are formed and deposited in serosa cells, which are dark brown; The plasma membrane cells of non-diapause eggs do not form pigment and are still light yellow. Silkworm-one of the most important economic insects in ancient China. The economic value of silkworm lies in silk. Silk is one of the main textile raw materials. China was the first country to use silk. In ancient history, there was a legend that Fuxi "transformed silkworms" and Leizu "taught people to raise silkworms". It is also said that the imperial concubine Xiling of the Yellow Emperor was the first person to raise silkworms. Archaeology in the Neolithic Age shows that before 2750 BC, the ancestors of Qianshanyang in Xing Wu, Zhejiang Province had woven silk sheets, ribbons and silk threads with silk. In the 3rd century BC/KLOC-0, names such as mulberry, silkworm, silk and silk were found in Oracle Bone Inscriptions. Silk, together with hemp, ramie and later cotton, is the main clothing raw material for China people, and sericulture has become an important part of China's agricultural structure. In thousands of years' practice, people in China have accumulated rich experience in sericulture, which is mainly reflected in the prevention and treatment of silkworm diseases. During the Shang and Zhou Dynasties, silkworms were kept indoors. During the Warring States Period (475-22 BC1year), there was a special silkworm room, which paid attention to the prevention and control of silkworm diseases and adopted the technology of bathing silkworm eggs. Raising young silkworms at constant temperature in the late 3rd century A.D. shows that the relationship between silkworm growth and temperature was known at that time, but it was not until Yuan Dynasty that the temperature required for each stage of silkworm growth was specified in detail in Shi Nong Yao. The Jin Dynasty has already known the microparticle disease and softening disease of silkworms, and called them "black and thin" and "pseudo-silkworms". According to Qi Shu Yao Min, in the 1930s, people also selected cocoons and preserved them in salt to prevent silkworm diseases. During the Song and Yuan Dynasties, the prevention and control of silkworm diseases went further. In addition to salting, cocoon storage methods also appeared sun exposure and cage steaming. At the same time, as the main means to control silkworm diseases, the silkworm bath method has also been improved. In the early days, silkworm bathing was mainly carried out in Sichuan. Cinnabar warm water bathing appeared in Song Dynasty, and natural bathing appeared in Yuan Dynasty, which used low temperature to select the best and eliminate the bad. The relationship between silkworm diseases and damp-heat, air-cooling was discussed in Agriculture Book by Chen Fang, and the relationship between silkworm diseases and leaf quality was summarized in Agriculture Sang Yaoji. In the Ming Dynasty (1368- 1664), dew, lime water, salt water and other methods appeared. In order to improve the disease prevention ability of silkworm, excellent varieties are cultivated by hybridization, and there are also methods to eliminate diseased silkworm and prevent its spread. China sericulture technology has been in the leading position in the world for a long time, which has made great contributions to the development of sericulture in the world. In BC 1 1 century, sericulture technology was introduced to Korea with Kiko and then to Japan. After Qin and Han Dynasties, China's sericulture technology was introduced to Central Asia, South Asia and West Asia through the world-famous Silk Road. In the middle of the 6th century, King Constantinople smuggled silkworm eggs from China to China through Indian monks, which was the beginning of sericulture in the West.

Cultural value

China is the first country in the world to raise silkworms and weave silk. On the outskirts of Xing Wu, Zhejiang Province, we found things left over by human beings for 5,000 years, including ancient silk fabrics, which proved that China would raise silkworms a long time ago. It is said that snail, the concubine of the Yellow Emperor, taught people to plant mulberry trees, raise silkworms, spin silk and weave cloth, so that everyone could have good clothes to wear. More than 2000 years ago, silk made in China was introduced to Europe. At that time, Europeans could not raise silkworms or spin silk. I don't know how such a beautiful fabric is made. Because Europeans like to buy silk, businessmen have to transport a lot of silk to Europe, so they have opened up a road to transport silk to Europe, which is the so-called Silk Road.

Many mulberry trees, including trees and shrubs, grow on the vast Yuan Ye in China. There are several kinds of insects living in mulberry trees. They eat mulberry leaves or tree trunks. Among these insects, one species of Lepidoptera can spin silk and form cocoons, which attracted the attention of our ancestors. This is a silkworm. Silkworms feed on mulberry leaves, spin cocoons, and then drill cocoons and feathers into moths. It has been found that this kind of cocoon shell can be soaked, and long silver thread can be drawn, twisted into thread or woven into silk. This is much better than flax and pueraria raw materials at that time. With the settlement of ancestors' life, in order to get more cocoons, people began to raise them artificially and moved indoors for domestication. Besides silkworms, there are tussah, camphor, dead and wild silkworms in China. Tussah (Antheraea pernyi i guren-meneville) belongs to the family Antheraceae, and is native to Laizhou (Yexian), Shandong Province. It is a silk-producing insect second only to silkworm in China, and now it exists in Liaoning, Henan and other provinces in large quantities. Tussah was first seen in Erya (BC 1200). Tussah silk was used as a tribute to the emperor 2700 years ago. Officially popularized in Han Dynasty, it was introduced and popularized in Song, Yuan, Ming and Qing Dynasties, and distributed in many provinces of China. Its main forage tree species are various leaves of Quercus. In the eyes of the ancients, silkworms were sacred animals. Spinning silk into cocoons and then turning it into flying souls is a beautiful and complete life cycle, which endows silk with mysterious and noble humanistic color and strong philosophical meaning. Silk culture has a long history of thousands of years. The ancient silk civilization is the treasure of the Chinese nation and China's great contribution to the world. It is the bond of friendship between China and the world. Silk is the messenger of friendship. Historically, embroidery and silk were often given to friends as high-grade gifts to show friendship. Silk culture has an indelible influence on promoting the process of human civilization. "Brocade" is the general name of colored jacquard silk fabrics. Brocade combines "gold" and "silk" into words, which means that brocade "weaves color as text, and its price is like gold". Brocade has become a fine product of traditional silk fabrics in China because of its complicated weaving technology, simple patterns and gorgeous colors. Myth of the Origin of Silkworm Breeding

Silkworm rearing is a fact that the unknown working people in ancient China mastered the laws of nature and put them into practice, but after all, the history is too long to trace its earliest origin, so there are all kinds of legends and myths. One of the legends is that sericulture was invented by Lei Zu, the concubine of the Yellow Emperor. In a mirror, Leizu, the daughter of Xiling family, is the princess of Yuan Di. She taught people to raise silkworms ... Later generations sacrificed them as the first silkworms. This statement is more common. Before liberation, the Silkworm Temple also provided the Xiling home for the first silkworm. In addition, there is a myth of looking for gods. According to legend, there were two fathers and daughters in ancient times. Father went out to work, leaving only his daughter and a horse at home. Daughter raises horses by herself. Because of poverty and loneliness, she missed her father who worked outside the home, so she joked to Ma, "If you can take my father back, I will marry you." Hearing this, the horse broke free from the reins and went straight to his father's work. Father was very surprised when he saw the horse, so he took it away and rode it. The horse looked at the direction and groaned. When my dad saw it, he guessed that something had happened at home and rode home. Animals are very caring, so their fathers feed them more carefully. But the horse refused to eat, and every time he saw his daughter coming in and out, he would beat his hoof with anger. The father felt strange and asked his daughter quietly. Daughter has to tell the truth. Father thought it was an insult to his family, so he shot the horse with an arrow, skinned it and dried it in the yard. Father is out again. The daughter and the girlfriend next door came to Mapi and laughed at Mapi and said, "Why do you want to marry a woman as a beast?" Why recruit such a fatal disaster! "The words sound just fell and Ma Pi suddenly fly up, a daughter swept away. The girlfriend next door was too scared to save her, so she had to tell her father. When my father came back, he couldn't find it anywhere. A few days later, they were found on a big branch. My daughter and horse skin become silkworms at the same time, living in trees with thick cocoons. Neighbors take it to raise it. Because the tree is a mulberry, and because the mulberry is homophonic with mourning, it is named silkworm, which is widely raised by ordinary people and is today's silkworm.

Market value

According to documents and cultural relics, our ancestors began to plant mulberry and raise silkworms as early as the Neolithic Age more than 5,000 years ago. The utilization of silk began at the end of the fishing and hunting era, and sericulture began at the beginning of the agricultural era, that is, the Yellow Emperor era. In the Zhou dynasty (BC 1066 ~ 256), sericulture became specialized and was managed by official inspectors. By the Warring States period (476 ~ 22 BC1), silk had reached a high level of development and became the daily clothing of the poor and the material of free trade. During the Warring States Period, many silk fabrics were unearthed in China, including Luo, Ling, Wan, Yarn, Crepe, Qi, Brocade, Embroidery and other products, and their patterns and colors reached an amazing level. During the Song and Yuan Dynasties (960 ~ 1368), silk production and silk weaving reached another peak, and the annual output of silk in the Song Dynasty reached 3.4 million. The rulers attached equal importance to silk industry and agriculture. There is often a record of "simultaneous development of agriculture and mulberry" in ancient books in China. The idiom "women don't silkworm, women get cold" reflects the ancient people's high understanding of sericulture. In ancient China, clothes were distinguished by silk and cotton and linen. Officials and rich people are all proud of their clothes, so the idiom "returning home with clothes on" came into being. Working people wear cotton and linen. Before the Tang dynasty (6 18 ~ 907), silk and grain were paid by the people, and the imperial court or government used silk as a reward for meritorious subjects. Nowadays, Tibetans and Mongolians all use silk (Hada) to express their respect and congratulations in welcoming guests, giving gifts, worshipping gods and daily communication etiquette. The development and popularization of the silk industry has also affected China's cultural life. In addition to many beautiful poems describing picking mulberry and raising silkworms, the idiom "tying one's own cocoon" is used to mean that people want to be good to themselves, but they suffer losses. In the Tang Dynasty, Bai Juyi had a saying, "Who will save the candle moth, the cocoon will be entangled." ; Buddhism in the Song Dynasty originally said that "listening to meditation is like a silkworm spinning its own silk." This poem. Because silkworms only eat mulberry leaves all their lives, what they spit out when they are old is its soft, smooth and white silk, so there is a poem "Spring silkworms must weave until they die" to praise those who have dedication. The development of ancient silk in China promoted foreign trade and cultural exchange. As early as 1 1 century, silkworm eggs and sericulture technology were introduced to Korea, Japan in the 2nd century BC, Turkey, Egypt, Arabia and Mediterranean countries in the 6th century ... sericulture technology was introduced to Europe in the 6th century, so silk represents an ancient oriental civilization and plays a very important role in cultural exchanges between the East and the West. Silk is a popular commodity. It and sericulture technology spread westward through the Silk Road, passing through grasslands, deserts, oases and mountains and rivers, and a number of famous towns such as Wuwei, Zhangye, Jiuquan, Dunhuang, Qiuci and Qin Shu emerged along the way. From the third year of Jianyuan (BC 138) to the third year of Yuanshuo (BC 126), Zhang Qian set out from the west of China and visited some countries west of Pamirs, and established contacts. Silk is an important product of China, so the ancient west called Chang 'an the Silk City and China the Silk Country. There is also a Silk Road in the south, which reaches Myanmar and India via Chengdu and Baoshan. On the eastern coast, ports such as Xuwen (Guangdong), Hepu (Guangxi), Penglai (Shandong) and Ningbo (Zhejiang) lead to Pacific islands and regions. At present, there are sericulture in Asia, Africa, Europe, Latin America, Oceania and many countries and regions, with an annual output of about 8 million tons of cocoons and 50,000 tons of silk. China ranks first in the world in cocoon production and silk production. Sericulture is distributed in all provinces, cities and autonomous regions except Qinghai, Tibet and Ningxia. Farmers in Zhejiang have always called this kind of insect that has made great contributions to mankind "silkworm baby". The silk it spits out has the light of pearls. Even with the rapid development of chemical fibers today, silk products are still known as the "queen of fibers", and some of its clothing characteristics are beyond the reach of other fibers. With the development of society and the improvement of living standards, sericulture has a very bright prospect. Male silkworms have 1 pair of testicles when they hatch, and about140 ~ 2 million nucleated sperm are formed at the 5th instar, and a large number of seedless sperm are formed in the middle and late pupae, but the latter cannot fertilize silkworm eggs. Female silkworms have 1 pair of ovaries when they hatch; After pupation 1 ~ 2 days, the ovarian tube in the ovary grows rapidly, and the broken ovarian membrane is free in the abdominal cavity. On the 9 th day, eggs are formed and move down to the fallopian tube. Two days before 1 ~ moth, the egg nucleus experienced 1 mature division and stopped at the middle stage. After mating, the sperm enters the egg, so that the egg nucleus, which stays in the middle of the first mature division, continues to divide due to stimulation and stops about 40 minutes after laying eggs. The second mature division begins about 60 minutes after the egg is laid and is completed in 20 minutes. About 2 hours after the egg is laid, the male and female nuclei fuse and begin to divide. The blastoderm is formed about 15 hours after delivery. Some cells in the blastoderm on one side of the egg cell hole gradually thicken into embryonic bands. About 24 hours after the egg is laid, the embryonic zone breaks away from the blastoderm and becomes an embryo, commonly known as an embryo. The remaining blastoderm is called serosa. The initial embryo has only/kloc-0 cells per layer, and then it forms two layers of cells: ectoderm and mesoderm, and endoderm only appears in the later stage of embryo development. The shape of diapause egg embryos does not change much during diapause. With the decrease of natural temperature, the diapause of silkworm eggs is gradually lifted. The optimum temperature for releasing diapause is about 5℃, but generally, diapause can be released gradually below 65438 05℃. In China, silkworm egg embryos are divided into 15 stages from diapause release to hatching (see table). Among them, the longest period is the critical period of production, after which the resistance of embryos to low temperature is weakened, so the longest embryo is the critical embryo of cold storage and the starting embryo of warming and promoting green. The inversion stage is the most vigorous stage for the formation of larval organs and tissues, which not only has obvious morphological changes, but also is very sensitive to external environmental conditions. Bivoltine species are affected by high temperature, long light and humidity during the green period, which can promote diapause eggs, otherwise they will produce non-diapause eggs. The ant body in the turning green stage has been basically completed, and its ability to resist low temperature has been enhanced. In production, the harvest period of ants can be adjusted by short-term refrigeration. After the embryo develops into an ant silkworm, it spits out alkaline intestinal juice to make the eggshell at the egg hole swell and soften, and then it is carved and torn into small pieces with the upper jaw to swallow, forming an hatching hole and crawling out. In the natural state, ants usually hatch at 5 ~ 9 am. Silkworm rearing technology-rearing of young silkworms

Plastic film mulching: used to raise 1 ~ 3-year-old silkworm. 1 ~ 2 years old, covered with polyethylene plastic film and folded around. Don't cover it during sleep, and continue to cover it after feeding the silkworm. 3 years old, only cover without mat. If there are fog drops on the film, wipe them before mulberry. In areas where conditions permit, silkworms of 1 ~ 3 years old should be bred in the young silkworm stage. Mulberry leaves should be collected from top to bottom according to leaf position. Mulberry leaves should be picked before 10 in the morning and after 3 pm to avoid picking in the hot sun. 1 ~ 2-year-old silkworms need to cut leaves to eat mulberry, and the standard of leaf cutting is usually twice the size of the silkworm. The amount of mulberries should be properly controlled in the short feeding period and mature period of all ages, and there should be enough food during the whole feeding period. Mulberry can be covered with plastic film four times a day. The amount of mulberry given each time is mainly controlled flexibly according to the development, appetite and residual mulberry degree of silkworm. If you have finished the mulberry you gave last time, you can increase the amount slightly next time, otherwise, the amount of mulberry you want to give will be reduced. Eating mulberry in the young silkworm stage only accounts for 5% of the whole age. Method of feeding mulberry: Before feeding mulberry, distribute silkworm evenly. 1 box maximum silkworm rearing area: 0 instar 1.07 ~ 1.2m2, 2 instar 1.6 ~ 4m2, 3 instar 4 ~ 10m2. Sand removal is to remove the residual mulberry and silkworm excrement on the silkworm bed. The first sand removal before sleep is called sleep sand removal, the first sand removal after sleep is called start sand removal, and the other time sand removal is called middle sand removal. Direct treatment methods include adding sleep nets and removing sleep in time to make the environment dry. When the silkworms are not well developed, it is necessary to raise green batches, put the green-headed silkworms at a higher temperature, and often cool the mulberry to catch up with a large number. Silkworms are hatched, so we should feed them at the right time. 90% ~ 95% of silkworms have light brown heads, indicating that they should be properly fed. The leaves are ripe, tender and fresh. In the young silkworm stage, before feeding the mulberry, the quicklime powder is evenly spread on the silkworm body and the silkworm bed, and each silkworm is picked up and sleeps once.

Feeding of strong silkworms

The fourth to the largest age is called big silkworm. During sericulture, we should prevent high temperature and humidity, strengthen ventilation and eat mulberry well. Mulberry leaves should be stored in a cool, damp, clean and hygienic mulberry storage room and laid flat on the ground. It is advisable to pick mulberries in the morning and reserve the amount for one day. 4, 5 years old, eating leaves or buds, giving mulberry 4 ~ 5 times every day and night. The fourth age accounts for 10% of the total mulberry consumption, and the fifth age accounts for 85%. Especially after the third day of the fifth age, eating mulberries is very fierce, so as to achieve a good satiety of mulberries. In hot and dry weather, the water content of mulberry leaves is low. After mulberry leaves are sprayed with water to feed silkworms, the water should be clean and the yield increase effect is obvious. During the big silkworm period, it is necessary to expand capacity and divide seats in time. Sand removal is an important work of health and disease prevention in the big silkworm stage. Sand removal should be done by net, not by hand. Silkworm disease prevention 1 is sprayed 1 time from the second and third instars when ants are collected, and from the fourth and fifth instars when mature silkworms are seen. If there is silkworm disease, once a day 1 time. Usage: Before feeding the mulberry, spread the powder evenly on the silkworm body and the silkworm bed, and give it to the mulberry after 10 minutes. Lime is disinfected at 1 year. Disinfect 2 ~ 4 instar silkworms and dormant silkworms 65438 0 times respectively. Disinfect the 5th instar silkworm, middle-aged silkworm and mature silkworm respectively 1 time. Sprinkle quicklime powder evenly on the silkworm body and silkworm seat before feeding mulberry. It is required to use it at least 3 hours apart from the silkworm disease prevention 1 ... Sprinkle quicklime powder at the door of the silkworm house every day, change clothes and shoes in and out, and don't throw dead silkworms around, but put them in a lime jar for centralized incineration. Wash your hands before and after feeding silkworms to remove sand. Silkworm excrement should be fermented far away from the silkworm house and should not be directly applied to mulberry fields. Using woven cloth to raise silkworms, you can put small wooden strips on the silkworm rack and spread woven cloth on the wooden strips to raise silkworms. When raising silkworms on the silkworm platform to remove sand, the effect of removing sand with a coiled net is very good. The method is to roll the silkworm net to half of the silkworm platform, sweep away the silkworm excrement below, then let go of the roll net and remove the sand from the other half. Silkworm is to put the cut mulberry strips and leaves on the silkworm bed to feed the silkworm. It can be fed on the silkworm platform or in the form of a bed on the ground (2.5% dimethoate powder is sprinkled on the ground to prevent ants, and then a layer of lime powder is sprinkled). Silkworm rearing in plastic greenhouse can not only save silkworm houses, but also improve the utilization rate of sheds. Generally, in a 3.3 m× 10 m greenhouse, two rows of 5-storey silkworm platforms can be set up, and 2 boxes of silkworm eggs can be raised in each period. A box of silkworms can be raised in the first phase of the 8-meter× 2.5-meter greenhouse. Serve food in time, according to the principle of cooking first. Upper layer density: 380 ~ 400 heads are folded, and the number of upper layers is calculated as 80% ~ 85% of the grid. A combination of manual picking and automatic lifting can be adopted. The temperature is kept at 22-25 DEG C.. The suitable humidity is 2.5℃, the illumination is even, and the environment is quiet, avoiding direct blowing of strong wind. Ventilation should be strengthened, and the wind speed should be kept at 0.5 ~1.0 m/s. After cocoon formation and pupation, the skin color of cocoon becomes Huang Shi, so cocoon should be picked in time. Cocoons are picked 6-7 days after reeling. When picking cocoons, first pick out the dead silkworms and rotten cocoons in the cocoons. According to the order of picking cocoons in batches, pick them first, then pick them lightly to avoid damage and bleeding of pupae. The picked cocoons should not be piled too thick, 2 ~ 3 grains thick, and kept in a cool, ventilated and dry place to avoid strong light. Silkworms only eat in the larval stage. The mulberry consumption of 1 silkworm is about 2 1 gram of fresh mulberry leaves (5.25g of dry matter), of which 85-88% are eaten at the fifth instar, and the digestibility is about 40%. The nutritional status of larvae directly affects the growth of silkworm body and the formation of cocoon silk and silkworm eggs. The essential nutrients of silkworm are: protein, carbohydrates, lipids, vitamins, inorganic salts and water. Protein is not only an important component of various organs and cells of silkworm, but also a basic raw material for silk gland cells to synthesize silk substances and ovaries to produce silkworm eggs. Carbohydrate is the main energy source of life activities. Sterols in lipids are precursors of ecdysone, which cannot be synthesized in the body and must be taken from food. Vitamins are indispensable bioactive substances for regulating substance metabolism, and most of them are auxiliary groups of enzymes. Inorganic salt is one of the components of cells, which plays a role in regulating the osmotic pressure and pH value of liquid inside and outside cells. Water accounts for about 85% of silkworm body weight, and it is the main component of silkworm body, which plays an important role in dissolving and transporting substances in the body, regulating and keeping the internal environment relatively constant. When blood water content is low, osmotic pressure increases, which hinders normal metabolism; If the blood water content is too high, the osmotic pressure will decrease and the pH value will decrease, which will also lead to the physiological disorder of silkworm body. Water comes from food, so the water content of food is closely related to the water content of silkworm body. The above nutrients are extremely rich in mulberry leaves. In addition, mulberry leaves also contain: ① food-attracting factors, such as citral, geraniol, geraniol, linalool and other volatile terpenoids; ② Bitter factors, such as β-sitosterol, isoquercitrin and morin; ③ Swallowing factors, such as cellulose, phosphate, silicate, inositol, vitamin C, etc., can stimulate the larvae to produce the requirements and actions of feeding, biting and swallowing. So mulberry leaves are the best natural feed. Artificial feed is also prepared according to the chemical composition of mulberry leaves. Formation of Silkworm-Silk Substance Spinning cocoon is an instinct for silkworm to adapt to the environment. Silk glands that produce and secrete silk substances are 1 pair of translucent and elastic tubular organs (Figure 4), which are formed in the later stage of embryonic development. The silk gland used in ants is only about 0.0 1 mg, which increases with age. However, before the third day of the 5th instar, due to the inhibition of juvenile hormone, the body weight did not exceed 5% of the body weight. The secretion of juvenile hormone stopped from the third day of the fifth instar, and a large number of mulberry leaves were mainly used for filament glands and synthetic silk substances. By the end of 5th instar, the silk gland can reach 65438±0.6g, accounting for 45-50% of the body weight. Compared with ant silkworm, the weight of silk gland is increased by about 6.5438 0.6 million times, but the weight is only increased by about 6.5438 0.6 million times. Silk substances, including silk fibroin and sericin, are protein composed of 18 amino acids. Sericin is produced in the middle silk gland, and silk fibroin is produced in the back silk gland. When silk fibroin is secreted into the gland cavity and pushed into the middle silk gland, it is surrounded by sericin. Each 5th instar silkworm produces about 0.35-0.6 grams of silk protein within 4-6 days after juvenile hormone stops secreting. Cocoon silk is generally colorless and transparent, but there are also silkworm varieties such as yellow cocoon, red cocoon or green cocoon. Yellow and red pigments are directly derived from pigments such as carotene in mulberry leaves; Green pigment is produced from flavonoids in mulberry leaves, such as isoquercitrin, quercitrin and rutin, through digestive tube. Whether cocoon silk is colored or not and the degree of coloring depends on the ability of digestive tract to penetrate and synthesize pigments, and the degree to which pigments entering the blood are absorbed by intermediate silk glands. White cocoon species have no color because no pigment enters the blood or is not absorbed by the intermediate silk gland. In addition, the environment also affects the depth of cocoon color. Generally, the pigment of silk lies in sericin. After reeling, it becomes white raw silk with the dissolution of sericin. The pigment of green cocoon also exists in silk fibroin, and it is still green after reeling.