Silkworm is a completely abnormal insect, which has to go through four stages of development: egg, larva, pupa and adult, for more than 50 days.
First instar: four to five days, second instar: three to four days, third instar: four days, fourth instar: six days, fifth instar: seven to nine days, pupal stage: fourteen to eighteen days, moth stage: three to five days.
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.
Extended data
Silkworm babies originated in China and were domesticated by primitive silkworms living on mulberry trees in ancient times. Their morphology and habits are very similar to those of wild silkworms that eat mulberry leaves today, and their serum precipitation reaction intensity is also the same. Crossbreeding can produce normal offspring. 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, people may collect primitive wild cocoons from mulberry forests for silk utilization. With the settlement of human life and the further understanding of the use of silk, people began to try to raise silkworms indoors. After long-term cultivation and selection, wild silkworm has gradually domesticated into a silkworm variety with today's economic characteristics.
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. In addition to the Pearl River Delta, there are East China Plain and Sichuan Basin as the main producing areas of China silk.
Silkworm babies are oligotrophic insects, and mulberry leaves are the most suitable natural food for silkworms. In addition to eating mulberry leaves, you can also eat zhe leaves, elm leaves, grape leaves, crow onions, dandelions and lettuce leaves, but eating these leaves will increase the mortality rate. The essential nutrients of silkworm include protein, carbohydrates, lipids, vitamins, inorganic salts and water.
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