Silkworm begins to hatch into silkworm ants from silkworm eggs, and after four times of peeling, it becomes a five-year-old silkworm baby and begins to spin silk and form cocoons.
First, about five years old.
The first instar (four to five days) is the first molting of the ant silkworm; Enter the second age (three to four days) after a "sleep" during molting and molting; Enter the third age (four days) after molting again; After the third molting, the silkworm enters the fourth instar (six days), and the fourth molting is also called dormancy. Enter the fifth age (seven to nine days) after sleep. At the end of the fifth age, the silkworm baby gradually stopped eating mulberry leaves, and the feces discharged changed from hard to soft, from dark green to green, and the body contracted and was transparent. At this time, it is called "cooked silkworm" by silkworm raisers. People put mature silkworms in special containers or cocoon traps, and silkworms spin silk and form cocoons. If the temperature is low or food is insufficient, the spinning time will be extended, but it will not exceed 30 days. It usually takes two days and two nights to spin silk and cocoons. Don't disturb it in the meantime, or you will be frightened, stop spinning and even die.
Second, the four signs before the silkworm baby spins silk and cocoons
1, loss of appetite: After the fourth peeling, the silkworm baby will continue to eat mulberry leaves, but the food intake will be significantly reduced. After about 7 days, the silkworm baby will stop eating completely and become very quiet.
2, the change of body shape: the precursor of silkworm spinning will become shorter and fatter, the whole body will turn yellow and shiny, and the chest will be transparent.
3. Feces change from hard to soft: Silkworm babies have more stools than usual, and the discharged feces change from hard particles to thin and soft, and the color of feces changes from dark green to light yellow. In addition to defecation, some yellow liquid will be discharged.
4, crawling around: At this time, the silkworm baby will hold its head and chest high, its body will keep swinging up and down, and its chest will shrink back and forth with the swing of its head. This is the position where the silkworm baby looks for cocoons, ready to spin silk and form cocoons.
3. The cocoon forming process of silkworm can be divided into four stages.
1. Mature silkworms first spit out spun silk, stick it on the tufting machine, then spit out spun silk, and connect the surrounding branches to form a cocoon-forming scaffold, that is, a cocoon-forming net. The cocoon net has no cocoon shape, but some soft and messy cocoon silk layers as the support for cocoon formation.
2. After the silkworm forms a cocoon web, it constantly spits out messy silk loops, thickens the inner layer of the cocoon web, and then spins in an S-shape, and the outline of the cocoon begins to appear, which is called a cocoon clothing. The silk fibers in cocoon shell are thin and brittle, with extremely irregular arrangement and high sericin content.
3. After the cocoon shell is formed, the cocoon cavity gradually becomes smaller, the front and rear ends of the silkworm body bend backwards into a "C" shape, and the silkworm continues to spit out cocoon silk, and the spinning mode is changed from S to S. O-shaped, start the process of cocoon formation.
4. When the silkworm's body is greatly reduced due to a large amount of spinning, the swinging speed of the head and chest slows down, forming a loose and soft cocoon silk layer.
Matters needing attention in sericulture:
The best food for silkworms is mulberry leaves. Mulberry is a deciduous Qiao Ben with oval leaves, serrated edges and smooth leaves. Mulberry leaves can be washed, dried or dried with water before feeding. Excess mulberry leaves can be put into food fresh-keeping bags and stored in the refrigerator. When feeding, take out room temperature 65438+ before feeding 0-2 hours in advance.