Scale insects form an exceptionally heterogenous group of obligate plant parasites. The wingless females, generally having gone through only 3-4 mould before adulthood, sit (almost) immobile on the plant, sap-drinking through en elongated stylus. The tiny males are winged and short-lived. The females produce was in a large variety of wax glands. In some of the more species-rich families more or less shield-like coverings have developed, that gave to group as a whole its name.
Coccoidea are most abundantly developed in the tropics, with a least 20 families.Through human activities many exotic species have arrived in glass-house cultures in temperate regions, but also in gardens and important open-air cultures in the Mediterranean Area.
Malumphy (2015a), Miller (2005a), Richards & Davies (1977a), Scale Net.