How many days does it take for silkworm eggs to hatch? How to keep it until next year? How to judge whether the silkworm eggs are alive or dead?

China is the first country in the world to raise silkworms to produce silk fabrics, which originated from the period of the Yellow Emperor and has a history of more than 4000 years. The silkworm goes through four different stages in its life, namely, egg, larva, pupa and adult. How many days does it take for silkworm eggs to hatch? How to keep it until next year? How to judge whether the silkworm eggs are alive or dead?

How many days does it take for silkworm eggs to hatch?

It takes about 15-30 days for silkworms to hatch from their eggs. Silkworm eggs are generally stored in the refrigerator, taken out and placed at room temperature. The most suitable temperature for silkworm eggs to hatch is about 25 ℃. Silkworm eggs will gradually turn purple-black, and larvae can hatch in about two weeks. After the larva bites through the eggshell, it first exposes its head, and then climbs out of the eggshell.

Silkworms reproduce with eggs. Silkworm eggs look like fine sesame seeds, about 1 mm wide and 0.5 mm thick. A female moth can lay 400 million 500 silkworm eggs. The weight of 1700-2000 silkworm eggs is about 1 gram and the diameter is 0. 2 cm. The color of silkworm eggs is light yellow or yellow when it is first laid, becomes light red bean or red bean color after 1-2 days, and then changes to grayish green or purple after 3-4 days, which is called fixed color. The outer layer of the silkworm egg is a hard egg shell with yolk and serosa inside. the embryo in the fertilized egg continuously absorbs nutrients during development and gradually develops into an ant silkworm. it crawls out of the egg shell and turns white or yellowish after the egg shell is empty.

The larvae just hatched from silkworm eggs are called the first instar silkworms, which begin to sleep after eating mulberry leaves for about 3 days, about 1 day, and then the second instar silkworms; the second instar silkworms begin to sleep for about two and a half days, about 1 day, and the third instar silkworms are the third instar silkworms; the third instar silkworms begin to sleep for about three and a half days, about 1 day, and the third and fourth instar silkworms. After about four days of sleep, the fourth instar began to sleep for about two days, and after about two days of four sleep, the fifth instar silkworm was about 6-8 days old. The silkworm stopped eating mulberry before cocooning, and the silkworm body contracted translucently. Usually, the first to third instar silkworms were called small silkworms and the fourth and fifth instar silkworms were called big silkworms.

How to judge whether the silkworm eggs are alive or dead?

There are three situations in which silkworm moths lay eggs.

1. The ones that turn brown or darker in two or three days are the diapause eggs that will come out next year.

2. Do not change color for a few days, or turn pink and turn red on the 8th, followed by non-diapause eggs of the ant silkworm.

3. It doesn't change color all the time, and then the unfertilized egg, that is, the dead egg, dries up.

How can silkworm eggs be preserved until next year?

The preservation of diapause eggs is divided into room temperature preservation and cold storage. The cold storage here is not frozen. If it is placed at a sub-zero temperature, it will lead to death.

1. Refrigerated storage

The method of cold storage is to refrigerate the silkworm eggs in a refrigerator of 5 degrees Celsius after confirming that the eggs have become dark and diapause 10 days after spawning. You can use disposable lunch boxes or plastic bags to store silkworm eggs.

The problem that should be paid attention to in cold storage in the refrigerator is that silkworm eggs should be kept dry without water droplets, and should not be placed in a refrigerated position to prevent freezing.

Generally speaking, after 100-120 days of preservation, silkworm eggs are basically free of diapause, although the two-day hatching rate may not reach the commercial standard, but the silkworm baby is still enough. If the time is less than 3 months, do not take it out, the hatching rate will be very low. However, do not refrigerate for too long, and the hatching rate of more than half a year will gradually decrease.

If the eggs laid in the first half of the year want to be reared in the next year, you can consider keeping the eggs at room temperature in the first half of the year, so that the silkworm eggs are less likely to develop without simulated winter, and then stored in the refrigerator between 10 and 12 months at the end of the year, and the next spring, when mulberry leaves germinate, silkworm eggs can be taken out and hatched.

For example, the following picture shows the silkworm eggs of the landlord in August last year, which had been preserved at room temperature, put them in the refrigerator in November, took them out at the end of March and hatched in the past two days.

2. Preservation at room temperature

Preservation at room temperature is also an effective way to preserve silkworm eggs, if preserved, it can also be preserved for a long time.

Generally speaking, room temperature preservation should pay attention to temperature control, shading preservation. The silkworm eggs can be placed in a cool place, such as a cold basement and a shoebox under the bed. Remember not to shine! No light! No light! Once exposed to light, silkworm eggs at room temperature for more than half a year will hatch one after another, and the consequences will be very serious.

The season of sericulture

In spring and summer, the growth cycle of mulberry should be roughly the same as that of mulberry to ensure an adequate supply of mulberry leaves.

The rearing method of silkworm

1. Feeding method: 4-5 instar silkworm is big silkworm period, the suitable temperature for growth is 25 degrees, the resistance of silkworm to high temperature, humidity and carbon dioxide is weak, mulberry consumption is large, and feces are large, so indoor ground rearing and outdoor scaffolding breeding can be used.

2. After getting the silkworm eggs back, the silkworm eggs are protected in a suitable environment to make the embryos develop normally. The specific methods are as follows: in the sterilized silkworm room, the silkworm eggs are laid in the silkworm plaque with the egg face up. On the 4th day, the room temperature is 24 ℃, the difference between dry and wet is 22.5 ℃, and on the 5th-10th day, the room temperature is 27 ℃, and the difference between dry and wet is 1.5 ℃. When the embryo develops to the later stage, when a small number of silkworm eggs are found to be cyan dots, the silkworm eggs are immediately covered with black cloth. After about 40 hours, that is, 4-5 before dawn on the third day, the dark black cloth is removed, the silkworm eggs are wrapped in white paper, and the eggs are exposed to light. Let the ant silkworm bite through the egg shell and hatch.

3. The main technical measures for rearing big silkworms are as follows:

⑴ improve the environment and do a good job of ventilation and anti-boredom.

⑵ sets up a shed for shade to prevent hot air from entering the silkworm room.

⑶ silkworm pedestal thinning, low release, frequent thin feeding.

⑷ should do a good job in mulberry garden management, ensure the quantity and quality of mulberry leaves at 5 years old, make silkworms eat well, and prevent silkworms from eating old hard leaves, over-tender leaves, malnourished leaves and water-deficient leaves.

Details that need to be paid attention to in sericulture

1. Sand removal before bedtime. This is to avoid excessive accumulation of silkworm feces, the bacteria are very easy to breed and spread, and then invade the silkworm during the dormancy period.

2. Silkworms do not eat or move during sleep, and mainly rely on the nutrients absorbed by mulberry before sleep to maintain their life activities. So be sure to eat and sleep. If you stop giving mulberry prematurely, it will cause hungry sleep, while hungry silkworms have weak physique, poor resistance and easy to get sick.

3. The silkworm has weak resistance to all kinds of external interference during the sleeping period, so we must pay attention to the protection during sleep.

When 95% of the silkworms are asleep, they should be sprinkled with fresh lime powder and silkworm medicine "Disease Prevention No. 1" to prevent the invasion of germs. If a small number of silkworms do not eat mulberry and do not sleep, it is because it has not found a place to sleep. At this time, it is necessary to put some mulberry leaves and sleep in batches.

4. Bombyx mori is a variable temperature animal with an adaptive range of 20-30 ℃. Spring silkworms often encounter a low-temperature and humid climate, focusing on warming and dehumidification. The summer silkworm period is hot and humid, and the key point is to cool and dehumidify, maintain the air circulation in the silkworm room and remove the muggy heat. If the autumn silkworm meets high temperature and dryness, it should be moisturized indoors, combined with disinfection, that is, fresh lime powder and bleaching powder can be used to spray water on the ground and wall; the cloth can also be drenched and hung on the silkworm rack to keep the silkworm room moist and avoid molting difficulties and semi-molting.