The growth cycle of the silkworm is about forty days, and its development is related to temperature, humidity and food. Generally, it is 10-11 days for the cataplasmic stage and about 25 days for the larval stage. Specifically, it is 4-5 days for the first instar stage; 3-4 days for the second instar stage; 4 days for the third instar stage; 6 days for the fourth instar stage; 7-9 days for the fifth instar stage; 14-18 days for the pupa stage; and 3-5 days for the moth stage.

1, eggs hatching: after 8-9 days of greening period, the baby silkworms from the eggs hatch out, just out of the silkworms and black and small, commonly known as ant silkworms.

2, the first age: the color of the first age of silkworms from black to dark brown, eating mulberry time 3~4 days, not much to eat. After entering the sleep period will be the first molt, sleep period time 8~12 hours.

3, the second age: the silkworm body grows obviously, the color becomes lighter, the time of eating mulberry is about 3 days, the sleep period of 8~12 hours.

4, the third age: silkworm body color becomes light brown, food began to increase, about 4 days later into the sleep period. 1 ~ 3 age of silkworms are generally referred to as small silkworms, 10 ~ 14 hours into the period of large silkworms.

5, four age: into the big silkworm period of the silkworm development is very fast, the amount of food increased significantly. 4 age time is generally 5 days, sleep period is very long, generally known as the big sleep period, sleep period of up to 30 ~ 40 hours.

6, five age: mulberry silkworms eat the largest amount of leaves in the period, about 7 days of leaf eating accounted for more than 75% of the total amount of leaf eating. 7 days later, the silkworm body began to shorten, bright, commonly known as ripe silkworms, ripe silkworms are no longer eating, began to spit silk cocoon.

Expanded Information

Silkworms are metamorphic insects, the most common is the mulberry silkworm, mulberry silkworm originated in China, its development temperature is 7 ~ 40 ℃, feeding temperature for 20 ~ 30 ℃. The baby silkworm lives on mulberry leaves, and its body becomes white when it keeps eating mulberry leaves.

The silkworm has a strong appetite. They eat mulberry leaves around the clock, so they grow very fast, commonly known as silkworms eat whales. There are suction cups on their feet that can suck on rough objects. When the color of their head turns black, it indicates that they are about to molt. After four molts their bodies will turn light yellow and their skin will become tighter, indicating that they will wrap themselves in a silk cocoon in which they will metamorphose into chrysalises.

If the pupa is allowed to metamorphose into an adult and naturally dissolve the cocoon and burrow out, the silk threads will become too short to be used for spinning and weaving because of the holes in the cocoon, so the cocoon should be placed in boiling water to kill the pupa before it breaks and to make the cocoon easy to dismantle.