Life Cycle and Uses of the Chinese Tussah Silkworm

The Chinese tussah silkworm (Antheraea pernyi) is a fascinating insect with a rich history, valuable silk production capabilities, and diverse applications, playing an important role in both textile and other industries.

1. Origin and Habitat

The tussah silkworm is native to China and has been domesticated for centuries. It is considered a temperate economic insect, thriving in temperatures ranging from 8 to 30°C, with optimal growth occurring between 22 and 24°C. While primarily found in China, smaller populations exist in North Korea, India, Japan, and some areas of the former Soviet Union. These silkworms were originally wild insects that lived on hillside tussah trees and were later domesticated, leading to the names “wild silkworm” or “mountain silkworm”.

2. Life Cycle

Like other silkworms, the tussah silkworm undergoes complete metamorphosis, progressing through four distinct stages: egg, larva, pupa, and adult.

3. Feeding Habits and Growth

Tussah silkworms primarily feed on the leaves of various oak trees (Quercus genus), including Tussah, Mongolian Tussah, and Quercus. They can also consume other leaves, such as artemisia, clover, chestnut, maple, pear, and apple leaves, but must begin feeding on these from the ant silkworm stage; switching to new leaves during feeding often results in refusal to eat or anorexia. Young silkworms prefer tender leaves, while mature silkworms eat ripened leaves.

During their larval stage, which lasts about 50 to 54 days in spring and 46 to 50 days in autumn, silkworms molt four times, with each molt increasing by one instar. Most of their feeding occurs during the later larval stages, especially the fifth instar. The weight of a silkworm at maturity is significantly higher than at the beginning of the larval stage.

4. Variety and Selection

Tussah silkworms are categorized into various breeds based on characteristics such as chemistry, body color, behavior, cocoon shape, and silk quantity. These varieties are usually named after specific traits, locations, or breeding numbers. Hybrid varieties are often selected for silk production in different regions.

5. Cocoon Formation

After reaching maturity, tussah silkworm larvae instinctively begin to spin cocoons. This crucial step provides a protective environment for the pupa, allowing it to either undergo diapause (a dormant state) for overwintering or continue to develop into an adult.

6. Economic and Industrial Uses

Tussah cocoons are a valuable resource, notably in the production of high-quality silk. This particular silk is often used for luxury clothing. Beyond textiles, tussah silk has applications in the military, chemical, and power supply industries. Furthermore, the pupae and moths are used as raw materials in chemical, pharmaceutical, and food sectors, while tussah eggs are used as intermediate hosts for biological control of agricultural pests, such as using Trichogramma to combat corn borers.