Once the crawler settles and inserts its mouthparts into the plant to feed it will often remain there for the rest of its life. The secretory glands on the bodies produce waxes and other materials used to construct various kinds of protective coverings. Adult males are non-feeding, mobile and winged so they can find females. Coccinea are major pests on many crops, ornamentals, and fruit and nut trees. Most damage is from feeding on plant sap and from a toxic reaction in plant tissue to the insects' saliva.
Some damage also occurs from growth of sooty mold on the honeydew the insects produce.
Galls and other plant deformations are caused by some species. Except for some mealybugs, which readily move in all stages from one plant to another, Coccinea do not seem to be significant vectors of plant diseases. A wide range of arthropod predators and parasitoids help keep them in check. A few Coccinea are or were of beneficial importance. Lac, secreted by a few families, is processed for shellac and varnish.