Silkworms provide us with several valuable products, most notably:

• Silk: Silkworms are famous for producing silk, a natural protein fiber. The silk is harvested from the cocoons they spin during their pupal stage.
• Silkworm pupae: In some cultures, silkworm pupae are eaten as a food source and are rich in protein and other nutrients.

Source: Britannica - Silkworm