The growth process of silkworm babies:
1 and 1 age:
The newly hatched silkworm is 1 year old. Its body is brown or red, small, with fine hairs on its surface and its head is red and black, like an ant without legs. Also known as ant silkworm, it is about 2 mm long and 0.5 mm wide.
Ants and silkworms are fragile, and they will die if they are hungry for 2~3 days, which is why a large number of dead ants will be found when friends open the container of silkworm eggs in spring.
2. Second instar silkworm:
A few days later, the ants kept eating, and the skin color at the junction of head and chest became lighter, and the body length could reach 4~5 mm at the end of the age. At this time, the skin of 1 silkworm is obviously shallow, the epidermis is tight, the head and chest are swollen, and it is ready to molt.
The head of the 2nd instar silkworm is still red and black, like a glass ball played by children. The back and chest are white, and the back and abdomen are gray. Compared with 1 silkworm, the body color of the second instar silkworm has obviously turned white, and the half-moon grain of the common spotted silkworm can be faintly seen. At the end of the second stage, the body length is about 1 cm. The characters that can be distinguished in the second stage are brown spot (tea spot), common spot and yellow blood silkworm.
3. Third instar silkworm:
The 3-year-old silkworm can clearly distinguish the characteristics of silkworm eggs, and its head is no longer black, but gray. Similar to human adolescence, silkworms at this stage may be a bit "ugly", waiting for a transformation. Body length at the end of the third stage 1.5~2 cm. Characters that can be distinguished by age in the three stages are: Hei Hu, high spot, black spot, flat spot and some hybrid silkworms.
Fourth instar and fourth instar silkworms
The 4th instar silkworm has the thinnest body, lighter head and grayish white. If the third age is "puberty", then the fourth age is "female size 18 changes", and the markings are very obvious. At the end of the fourth instar, the body length is 2~3 cm.
Silkworms eat more than 80% of mulberry leaves in the 4th to 5th instar, and then cocoon. If not fed in time, the silkworm age will be obviously prolonged. The distinctive features of the 4th instar are: Dragon horn, quail spot, multi-star and partial hybrid silkworm.
Stage 5, 5 Silkworm, Mature Silkworm and Pupation
The head of the 5th instar silkworm is gray-white, and the skin of the newly molted silkworm is flabby, with large abdomen, obviously open tail and foot, and sufficient suction. With the continuous feeding, the 5th instar silkworms gradually become obese. Generally, they don't spit floating silk before cocoon formation, and they can hear obvious biting sound when eating mulberry.
In the middle and late fifth instar, the body length can reach more than 5 cm, then the digestive system gradually degenerates, the weight and body length shrink, and the body gradually becomes bloated. The 5th instar silkworm ate less on the 2nd day after molting and the 2nd day before spinning, but ate more at the middle stage.
Extended data:
Mature silkworms spin silk:
Silkworms make their own cocoons. A few days later, with the emptying of silk glands, the silkworm's body shrank into a spindle shape, making it difficult to move. It is also called pre-pupa at this time.
Butterfly can directly observe the pre-pupation process because it rarely cocoons, while silkworm's pre-pupation process can only be observed after cocoon cutting. Some have pupated, and the skin that has just formed pupae is pale yellow, and then gradually turns yellow-brown.
As for the silkworm rearing period, the author searched for an inseparable content and made a slight modification: 1 stage age of 3-5 days, 2-4 days, 3-5 days, 4-6 days and 5-9 days, totaling about 17-29 days.
Generally speaking, the lower the temperature, the longer the silkworm period, the bigger the body shape, and vice versa. Spring silkworms are generally older and older than autumn silkworms. In the hot and high temperature environment, the whole silkworm period of Dazao (silkworm genome sequencing variety) is even about 15 days.