Kerria lacca

Kerria lacca is a species of insect in the family Kerriidae, the lac insects. These are in the superfamily Coccoidea, the scale insects. This species is perhaps the most commercially important lac insect, being a main source of lac, a resin which can be refined into shellac and other products. This insect is native to Asia.

Kerria lacca produces a dye and a wax as natural secretions. The life cycle of this scale insect proceeds with the first instar of the larval stages, which are known as "crawlers". Larvae in this stage crawl along the branches of their host plants and feed on the phloem. As they pierce the branches to reach the phloem, they cover the holes with their wax secretions.

More than 400 host plants have been noted. Three are used for the majority of commercial cultivation of the insect: palas (Butea monosperma), kusum (Schleichera oleosa), and ber (Ziziphus mauritiana).

There are at least two strains of the insect that are characterized by aspects of their life cycle and their host plant preferences.

The species was described and given the binomial name Coccus lacca in 1781 (published formally in 1782) by the Scottish surgeon James Kerr (1737–1782) in Patna. It was then placed a new genus named after Kerr as Kerria in 1884 by Adolfo Targioni-Tozzetti (who had noted that it did not belong to Coccus even in1868).

Natural predators of this species include several parasitoids, such as the parasitoid wasps Tachardiaephagus tachardiae and Coccophagus tschirchii. Predators include the moths Eublemma roseonivia and Holcocera pulverea. These moths can interfere with lac cultivation in India.

These insects, as well as many types of fungal pathogens, form an ecological web that is important to local biodiversity.

Kerria lacca has been reported as a pest insect. It is reared on ber trees (Ziziphus mauritiana), but these trees are also cultivated for fruit, the Indian jujube. K. lacca sometimes invades Indian jujube orchards and degrades the fruit crop.