How to distinguish the male and female of silkworms?

How to distinguish the male and female of silkworms. The most reliable feature to identify the male and female of silkworm babies is the eighth and ninth abdominal segments: the ventral surface of the eighth and ninth female silkworm segments. There are four small transparent dots; there is a small transparent dot in the center of the ventral surface of the ninth segment of the male silkworm.

zhidao.baidu/question/50186834

How to distinguish the sex of silkworms? You can identify the silkworm larvae when they are before they molt for the first time. The small and black ones are males, the relatively lighter and larger ones are females. When they grow up, they all turn white. Look at the buttocks. The pointed ones are male and the round ones are female.

How to distinguish male and female silkworms? Some characteristics of silkworm eggs, larvae (silkworm babies), silkworm chrysalis, and silkworm moths can all be used to identify the male and female gender. But the most widely used method is to identify the sexes of old silkworm babies, silkworm pupae and silkworm moths.

The most reliable feature for identifying male and female silkworms is the eighth and ninth abdominal segments: female silkworms have four small transparent dots on the ventral surfaces of the eighth and ninth segments; male silkworms have a transparent dot in the center of the ninth abdominal segment. Smaller.

To identify the characteristics of male and female pupae, we also use the structures at the eighth and ninth abdominal segments. There is a straight line in the center of the ventral surface of the eighth and ninth segments of the female pupa's abdomen, which separates the eighth and ninth segments; while there is a pair of small protrusions in the center of the ventral surface of the ninth segment of the male pupa's abdomen.

As for the distinction between male and female moths, in addition to identifying characteristics such as the size of the antennae and abdomen, the most reliable method is to identify the external genitalia of male and female moths. For example, there is a black bone plate near the mating hole of a female moth, and a black bone plate near the mating hole of a male moth. There are pairs of grippers, etc.

It takes about 4 days for silkworms to pupate after getting on the cob. The pupa body is spindle-shaped and divided into three body segments: head, thorax and abdomen. The head is very small, with a pair of compound eyes and a pair of antennae on its ventral surface. ; The chest has 3 body segments, 3 pairs of thoracic legs, and 2 pairs of wings; the abdomen has 9 body segments, and there is an "X" shaped line in the middle of the ventral surface of the 8th abdominal segment, and there is a small brown dot in the middle of the ventral surface of the 9th abdominal segment. These are the body surface characteristics of male and female in the pupa stage, which are often used as a basis for identifying males and females in silkworm breeding. When silkworms just pupate, the color of the pupa is light yellow and the pupa body is tender and soft. As the pupa ages, it gradually changes to yellow, tawny and brown, and the pupa skin also gradually hardens. The pupal stage lasts for about 12 to 15 days. When the pupal body is softened again and the pupal skin is moderately wrinkled and earthy brown, it is close to the hair moth. Silkworm chrysalis is rich in nutrients and can be used as food or feed, or pupal oil and pupal protein can be extracted as chemical or pharmaceutical raw materials

How to identify the male and female silkworms? When I visited the Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, I found many researchers dissecting silkworms, and the baby silkworms were very cute. I asked these researchers if it was possible to visually distinguish the sex of silkworms, but learned that identification could only be done in the pupal and adult stages. So if the silkworm farmer needs to know as early as possible whether he is raising male or female silkworms in sericulture production so that he can adjust or select according to his own needs, can the sex be identified in the larval stage? Researchers say they can try to use advanced DNA marking technology to identify the sex of silkworm larvae.

1. Experimental significance:

1. Bombyx mori is an economic insect and is closely related to humans. Silk is an invention in ancient my country and has made important contributions to human material and spiritual civilization. Through the breeding of silkworms, we can have a deeper understanding of the life history of silkworms, and at the same time, we can better understand the process of silkworm production.

2. Almost all living things on the earth use DNA (deoxyribonucleic acid) as genetic material. DNA is the basis of life activities. Through this experiment, you can understand and master how to extract DNA from biological tissues. The silkworm DNA obtained from the experiment can be used for genetic analysis of silkworms in the future, studying the quality control mechanism of silkworm silk production, and at the same time providing guidance for silkworm breed selection to cultivate excellent silkworm varieties. In addition, this experiment is the basis of biological experiments, and all experiments on silkworm molecular biology are carried out on this basis.

3. The early gender differentiation of silkworms is of great significance to silk production. Due to their strong physique, male silkworms are less likely to be infected by pathogenic bacteria and produce more silk than female silkworms. At the same time, female silkworms have more demands for seed production, so it is hoped to raise more male silkworms in sericulture production. However, identifying the gender of silkworms by their appearance can only be done in the pupa and adult stages. This experiment can identify the gender of silkworms in the larvae stage, which solves the problem that silkworm farmers need to know as early as possible whether they are raising male or female silkworms in sericulture production. This difficult problem of silkworms has important economic significance in sericulture production. In addition, the key to distinguishing male and female silkworms is the difference in genetic information from the male and female parents. Through the development of relevant markers, the basic laws of biological inheritance can be understood.

2. Experimental purposes:

1. Master the methods of raising silkworms.

2. Preliminarily master the extraction methods and principles of silkworm DNA.

3. Understand the principle, significance and operation method of measuring nucleic acid concentration and purity by UV spectrophotometry.

4. Use DNA marker technology to identify the sex of silkworm larvae.

3. Experimental Principle:

1. Silkworm rearing:

Silkworms are completely metamorphosed insects and go through four stages: egg, larvae, pupa and adult in one generation. completely different developmental stages. Adults mate and then give birth to the next generation, completing the entire life cycle.

2. DNA extraction

DNA is the basic content of biological life information. Through extraction, the DNA of the target individual is obtained for further analysis. In DNA extraction, the purity of the obtained DNA is a measure of the success of the experiment. During the process, the impurities that have the greatest impact on the purity of the DNA: proteins and RNA must be removed. The key points are: 1) Use proteinase K to enzymatically digest proteins; 2) Use organic solvents to denature proteins, and then precipitate proteins through centrifugation; 3) Use RNase to enzymatically digest RNA to avoid the impact of RNA on DNA during extraction< /p>

3. Gender distinction

The silkworm is a type of eukaryotic cell organism. Their genetic material comes from their male and female parents respectively. The maternal zygote is ZaW and the paternal zygote is ZbZb. The difference between Za in females and Zb in males will be reflected in the offspring. If it is a female offspring, the zygote is ZbW. If it is a male offspring, the zygote is ZaZb. Reflected in the DNA bands, there is one band for females and two bands for males.

IV. Experimental materials:

1. Bombyx mori eggs (used for raising silkworms).

2. The fifth instar larvae of silkworms obtained from breeding (used for DNA extraction and gender identification).

V. Experimental steps:

1. Breeding of silkworms:

Bombyx silkworms reproduce from eggs and hatch into larvae in about 10 days. The eggs will turn black about 2 days before they hatch. The newly hatched larvae are brown and resemble ants, and are also called ant silkworms. Ant silkworms grow rapidly by feeding, and their body color gradually turns pale and turns bluish white. When the larvae grow to a certain extent, they need to shed their old skin and grow into a wider new skin, which is called molting. During the molting process, silkworms need to sleep while the new skin is forming, which is called sleep. Sleep is also the boundary that divides the age of silkworms. After ant silkworms eat, they are called the 1st instar silkworms, after the first sleep, they are called the 2nd instar silkworms, and so on, after the fourth sleep, they are called the 5th instar silkworms. Each instar...the rest of the text>>

How to distinguish male and female silkworms Pictures There are male and female silkworms, but they cannot be distinguished until they are 4-5 years old. Male and female, female silkworms have a pair of small milky white dots (fourth point) symmetrically on the ventral surfaces of the eighth and ninth abdominal segments at the tail of the silkworm, which are called the pregenital disc and the postgenital disc respectively, while the male silkworm has There is a small oval point in the center of the ventral junction of the eighth and ninth abdominal segments, called a small sac.

How to distinguish male and female silkworm chrysalis? Two methods: 1. Look at the antennae. The wider ones are male, and the smaller ones are female. 2. Look at the 2nd and 3rd segments from the bottom of the abdomen. The ones with dots are male, and the ones with grooves or come out. The male moth is smaller, while the female moth is larger - especially the belly.

The yellow and white color of your cocoon may be due to the silkworm species, or it may be that the cocoon is contaminated. It has nothing to do with the male or female.

How to distinguish the male and female silkworms that turn into butterflies by looking at the silkworm shell

How to distinguish the male and female silkworms, answer