What insect's resinous secretion is used to produce shellac?

The insect whose resinous secretion is used to produce shellac is the lac insect. The principal commercial species is Kerria lacca, a scale insect native to parts of South and Southeast Asia.

Female lac insects settle on host trees, pierce the bark and feed on plant sap. As they grow and reproduce, they exude a resin that coats the branches. The harvested, resin-covered twigs are called sticklac. Crushing and washing remove much of the bark, insect material and other impurities, producing seedlac.

Seedlac is then heated or dissolved and filtered to make shellac, which is sold as flakes or dissolved in alcohol. It forms a durable, glossy coating used on wood, food as a glazing agent, pharmaceuticals and some specialty finishes. Shellac was also historically used as an electrical insulator and in gramophone records.

The resin is not a silk cocoon, although the insect’s tunnel-like coverings are sometimes described that way informally. Lac insects are also distinct from cochineal insects: cochineal produces a red dye, while lac primarily supplies resin for shellac.