Sex Discrimination of Silkworm

Technical measures to identify male and female silkworm species in the production of hybrids or when mating in different moth areas and different strains. There are many ways to identify males and females, some in the developmental stages of silkworm, pupa, moth, etc.; some are distinguished by the characteristics of genitals, weight, and volume; some are distinguished by limited traits (egg color, silkworm body markings, cocoon color); It is identified manually and mechanically by the naked eye. At the beginning of production, the silkworm body identification method was adopted. After the multi-filament varieties were promoted, the cocoon layer was thick and the moths did not easily climb out of the cocoon shell. The pupal body identification method was adopted for the pupal stage if the cocoon needs to be removed; Weight machine identification.

Silkworm body identification

According to the different characteristics of the female and male external genitalia of the silkworm body. The female silkworm’s genitals are divided into progenital buds (front gonads) and posterior genital buds (posterior gonads). The progenital buds are located on the left and right sides of the ventral surface of the 11th link. They are two milky white dots penetrating through the cortex, and the posterior germs are located at the 12th link. The left and right sides of the ventral surface, the oblique front of the tail foot, and the horizontal line near the base of the abdomen foot are two small points. The reproductive bud of the male silkworm is a small sac-like body, or Hexian gland, located at the central end of the ventral surface of the 11th link, attached to the skin of the 11th link and the 12th link. The identification time is appropriate after 36 hours have passed from the 5th instar silkworm. Silkworms that have recently eaten are easy to get injured, while the male and female characteristics of silkworms in the late 5th instar are difficult to identify.

Pupa identification

The female pupa is relatively hypertrophic, with a blunt and rounded abdomen end. At the 8th link (the 5th link of the abdomen), there is an X-shaped longitudinal line on the ventral surface. The link (the sixth link of the abdomen) has a small depression in the center of the ventral surface. Identification should be carried out after the cocoons are qualified and the cocoons are selected. It is appropriate to start when the compound eyes are colored to black. Premature pupa body is tender and easy to get injured and bleed, and the protection time of nakedness is long, which increases the chance of pathogen infection, leading to increased dead pupae and low moth rate; too late affects the regulation of moth. In order to reduce the loss of pupal stage, it is better to be late. (Before identification, labor organization, material preparation, technical training, etc. must be done.) The identification procedures are divided into: cocoon cutting, pupal identification (initial inspection, re-inspection), and pupal sharing.

1. Cutting of cocoons should be carried out in sequence according to the order of the species. When cutting the cocoon, the incline on the front and upper side of the knife should be used to avoid cutting the silkworm pupa. When pupa is inverted, the movement should be light and easy to prevent accumulation.
2. The pupa is divided into primary and secondary examinations. The primary examination should look over the head one by one, handle with care, and correctly separate the male and the female to prevent pinching the pupa; the secondary examination mainly focuses on the form of the pupa, selecting males from females and females from males. , Sui Jian Sui Fu.
3. The chrysalis is the silkworm chrysalis after re-inspection, and it is spread in the plaque. Naked pupae are protected. The plaque is covered with straw or chaff, 800-900 female pupae or 900-1000 male pupae are spread on each plaque. The density should be even, and the species should be marked. To facilitate the regulation of moths.