Moth larvae can cause considerable damage to stored products by feeding or by contamination by their own products, such as webbing (silk spun by moth larvae) or frass (larval refuse).
For example, clothes moths attack animal products such as wool, fur, skins and leather. Fibres are bitten off and the loose ends are discarded, thus leading to a greater loss of the product than is actually consumed by the insects.
Larval development is greatly influenced by the environmental conditions of temperature and food supply.