Sericulture and Silkworm Lifecycle
topic
Bombyx mori lifecycle: (1) egg stage (10-14 days incubation at 25°C, 60-70% RH), (2) larval stage (25-32 days, five instars with molting, consuming 20-25 kg mulberry leaves per kg cocoons, growing from 2-3 mm to 70-85 mm), (3) spinning cocoon (2-3 days, secreting 900-1500 m continuous silk filament in figure-8 pattern, forming cocoon 2.5-4 cm containing 0.3-0.9 g silk), (4) pupal stage (10-14 days metamorphosis inside cocoon), (5) moth emergence (if allowed—piercing cocoon breaking filament into short fibres reducing to waste silk). Commercial: cocoons harvested after 7-10 days in pupal stage, pupae killed by steam/hot air before moth emergence to preserve continuous filament.
Role
Understanding lifecycle critical for sericulture management—temperature, humidity, nutrition control affecting cocoon quality (shell ratio 18-25%, filament length, defects), with timing of harvest determining silk type (reeled continuous filament vs. spun staple if moth emerges) and pupae utilization (sold as animal feed, human food in Asia, recovering 30-40% of cocoon weight value).