The law of cocooning in silkworm spinning

The life of silkworm goes through four stages: egg, larva, pupa and adult. The larval stage of silkworm is called the stage of silkworm baby. Commonly referred to as @ # @ 250 eggs, refers to the breeding of larvae. The larvae go through four molting times from hatching to cocooning. As a result, the process of the larva is divided into five instar stages. For a period of time before molting, silkworms do not eat or move, which is called sleeping. From the first to the fourth instar, the silkworm sleeps four times, and the fifth instar silkworm no longer sleeps in the later stage, but forms a cocoon and pupates in the cocoon, thus completing the larval stage of the silkworm. The newly hatched silkworm is called ant silkworm, the newly molted silkworm is called silkworm, the sleeping silkworm is called sleeping silkworm, the silkworm that is about to sleep is called sleeping silkworm, and the silkworm that is about to spin silk and cocoon in the late fifth instar is called mature silkworm. According to the physiological characteristics of silkworm, the first to third instar is generally called small silkworm stage, and the fourth to fifth instar is called big silkworm stage. The length of larval stage varies with variety and temperature. Generally, the spring silkworm period is about 25m / m 28 days, and the summer and autumn silkworm period is about 20m / m / 22 days.

The process from cooking to cocoon picking of mature silkworms is called Jiazhong. The cocoon is usually divided into three stages: the cocoon position from the upper cocoon to the cocoon camp is fixed (forming a cocoon net) for the early stage (Prophase), the cocoon position is fixed to the end of silking for the silking period (middle stage), and the end of silking to cocoon picking is the pupation period (late stage). In the case of a temperature of 24 ℃ (75 ℃), the initial stage usually passes through 1 day and night. During the pupation period, after 2 days and nights from the end of silking to molting, the pupa of the initial pupae was milky yellow, and the skin was weak and easy to break. After 2 days and nights, the pupa gradually changed from milky yellow to yellowish brown, which was the suitable time for cocoon picking.

The elapsed time is not only related to temperature, but also related to silkworm varieties. The time of spring seed is long, and that of summer and autumn is short. It usually lasts about 7 days in spring, 5 days in summer, 6 days in Mid-Autumn Festival, and 8 days in late autumn. Cocoon picking mainly depends on the color of the pupa, yellowish brown in spring is better, yellow in summer and autumn is better, even tender can be picked.