Why do spiders sometimes eat their own web?

Building a web is expensive, so many spiders recover materials by consuming old silk. The silk proteins are broken down and reused to make new threads, which helps conserve nutrients in environments where prey is unpredictable. Spiders often rebuild parts of a web daily, especially in orb-weaving species that need sticky strands to remain effective. This behavior makes web building more efficient than treating silk as a one-time material. Recycling silk is one reason spiders can maintain elaborate traps without constant fresh protein intake.