What are the patterns of silkworms spinning silk and forming cocoons? A full explanation of the process

The life of a silkworm goes through 4 stages: egg, larva, pupa and adult. The larval stage of the silkworm is what people call the silkworm baby stage. What is usually called @#@250@#@ refers to the rearing of the larvae. From hatching to cocoon spinning, the larva must go through 4 molts. People therefore divide the course of the larva into 5 instars. During the period before molting, the silkworm does not eat or move, which is called sleeping. From the first to the fourth instar, the silkworm must sleep 4 times; in the later stage of the fifth instar, it no longer sleeps, but spins silk and forms a cocoon, and pupates inside the cocoon, thereby completing the larval stage of the silkworm. Newly hatched silkworms are called ant silkworms, newly molted silkworms are called risen silkworms, sleeping silkworms are called sleeping silkworms, silkworms about to sleep are called pre-sleep silkworms, and silkworms in the later stage of the fifth instar that are about to spin silk and form cocoons are called mature silkworms. According to the physiological characteristics of silkworms, the first to third instars are generally called the young silkworm stage, and the fourth to fifth instars are called the large silkworm stage. The length of the larval stage varies with variety and air temperature. Generally, the spring silkworm season is about 25-28 days, and the summer and autumn silkworm seasons are about 20-22 days.

The process from mature silkworms mounting the cocooning frame to harvesting cocoons is called cocooning. Usually, cocooning is divided into 3 stages: from mounting the frame to the cocoon-spinning position being fixed (forming the cocoon net) is the early stage (early period), from the cocoon-spinning position being fixed to the end of silk spinning is the silk-spinning stage (middle period), and from the end of silk spinning to cocoon harvesting is the pupation stage (late period). At a temperature of 24°C (75°F), the early stage generally lasts 1 day and night. In the pupation stage, from the end of silk spinning to molting and pupation takes 2 days and nights. The body of a newly pupated silkworm is pale milky yellow, and the body skin is soft and easily broken. After another 2 days and nights, the pupa body gradually changes from pale milky yellow to yellow-brown, and this is the suitable time for harvesting cocoons.

The duration of cocooning is related both to temperature and to silkworm variety. Spring varieties take a long time, while summer-autumn varieties take a short time. Generally, the spring season is about 7 days, the summer season about 5 days, the mid-autumn about 6 days, and the late autumn about 7-8 days. Cocoon harvesting mainly depends on the color of the pupa body. In the spring season, yellow-brown is best; in the summer and autumn seasons, yellow is best, that is, it can be harvested when slightly tender.