Silkworm, scientifically known as Bombyx mori, is in the family Bombycidae. Silkworm is a lepidopteran insect with four developmental stages: egg, caterpillar, pupa and butterfly. They only feed on food in the caterpillar stage which will bring various substances from the mulberry leaves for their growth through digestion and absorption into the amount of 1 in 3 of all nutrients. Half of the protein absorbed from mulberry leaves is used to produce silk. At the first 5 days of age, silk gland is only 6.36% of the silk weight.