Life History Of Silk Moth

The life history of the silk moth (Bombyx mori) is a classic example of complete metamorphosis and includes four major developmental stages: egg, larva (caterpillar or silkworm), pupa (inside cocoon), and adult moth.​

Stages of the Silk Moth Life Cycle

Egg: The cycle starts when a female silk moth lays 300–400 small, oval eggs, usually on the underside of leaves. Eggs hatch in 7–10 days in spring or under favorable conditions.​

Larva (Silkworm/Caterpillar): The emerging larvae are tiny and hairy, feeding voraciously on mulberry leaves. This larval stage lasts 3–4 weeks and includes several molts as the caterpillar grows considerably in size.​

Cocoon (Pupa): When fully grown, the caterpillar spins a cocoon around itself using liquid silk secreted from special glands. The cocoon is a protective shell made of a continuous silk filament. Within the cocoon, the larva transforms into an immobile pupa over 2–3 weeks.​

Adult Moth: The adult silk moth emerges from the cocoon, leaving behind the empty shell. Adults are short-lived, lacking functional mouthparts; their sole purpose is to mate and lay the next generation of eggs, restarting the cycle.​

Additional Details

The total life cycle from egg to adult typically takes 6–8 weeks.​

Silk is harvested by boiling the cocoon before the moth emerges to keep the thread continuous.​

Silk moths and silkworms are collectively vital for sericulture, with the silk produced exclusively by the larval (caterpillar) stage.​

This complete metamorphic cycle demonstrates dramatic changes in form, specializations for different life stages, and economic importance in silk production.​