The cochineal, Dactylopius coccus, is a scale insect in the family Coccidae, and is native to tropical and subtropical South America and Mexico. As a protective strategy, the cochineal produces carminic acid that deters predation by other insects, especially ants. Interestingly, the caterpillar of a pyralid moth (Laetilia coccidivora) takes advantage of this protective strategy by preying on cochineal scale and storing carminic acid in its gut to deter its natural enemy ant, Monomorium destructor. The common name of Dactylopius coccus is derived from the carmine dye (also known as cochineal) that can be made by extracting and drying carminic acid from this scale's body and mixing it with aluminum or calcium salts. Cochineals (the insects) are about 20% carminic acid by dry weight. Carmine dye production was developed in the 15th century by Mayan and Aztecs for coloring fabrics, and became a very valuable and highly prized Mexican export until the 1800s, when other countries (Guatamala, Spain, North Africa, Australia) developed means for cultivating the scale insect and large-scale production of carmine dye.

There is a rich history around the introduction of the cochineal and its host plant, Opuntia (prickly pear) cactus, to parts of the world where carmine production was attempted. This history includes the disaster of Captain Arthur Phillip, who in 1788 brought the cochineal and its host plant Opuntia cactus to Australia in order to establish carmine production in the new colony at Botany Bay. Although the cochineal soon died off, the invasive Opuntia cactus spread out of control until the 1920s, when it was finally regulated (and continues to be) by deliberate introduction of the cactus moth Cactoblastis cactorum, which is now in itself an invasive species to Australia. At the end of the 1800s development of synthetic pigments such as alizarin started to replace carmine and caused a decline in carmine industry, but carmine production has resurged in popularity of late, especially after many synthetic red dyes started to show carcinogenic properties, and is now used primarily for food, clothing and cosmetic coloring. The phrases "cochineal extract", "carmine", "crimson lake", "natural red 4", "C.I. 75470", "E120" refer to carmine dye derived from D. coccus.

Cochineal insects are soft-bodied, flat, oval-shaped scale insects. The females, wingless and about 5 mm long, cluster on pads of many species of Opuntia. With piercing mouthparts they feed on the plant juices, remaining immobile. The nymphs secrete a waxy white protective substance which makes them appear white or grey from the outside, though the true color of the insect’s body is dark purple, from the carmine pigment it produces. Individuals disperse to new host plants at the nymph stage (also called the crawler stage) mostly by wind, which catches the long waxy strings made by the nymphs. Unlike the females, adult males have wings, and are much smaller in size than females. Adult males live only long enough to fertilize the eggs so are seldom observed. Cochineals can be farmed in the "traditional method", by planting infected cactus pads or infecting existing cacti with cochineals and harvesting the insects by hand, or in a more controlled method in which small baskets called Zapotec nests are placed on host cacti to contain fertile females.

(Gibson; Wikipedia 2011)