stink bug, member of a large, widely distributed family (Pentatomidae) of true bugs with flattened, shield-shaped bodies. Most are 1/4 to 1/2 in. (6–12 mm) long. Those species whose hard upper covering, or scutellum, covers most of the abdomen are known as shield bugs, as name also applied to bugs of the family Acanthosomatidae. An unpleasant-smelling secretion is emitted from two glands on the thorax when stink bugs are disturbed.
Most stink bugs suck plant juices; some feed on other insects. Certain species, such as the brightly colored harlequin bug, are destructive to garden crops. The browm marmorated stink bug, an East Asian native that probably entered the NE United States sometime in the 1990s, has become a major agricultural pest in the Middle Atlantic states. In the fall, this species seeks shelter inside buildings, becoming a household nuisance.
Many stink bugs are protectively colored in brown or green; a black species is common on blackberries and raspberries. The eggs are usually shaped like squat barrels with hinged lids and are glued upright in double rows to the leaf surface. The young mature in five nymphal stages (see insect). Stink bugs of several species are used as human food in Mexico, Asia, and Africa. There are over 5,000 species, with several hundred in North America.
Stink bugs are classified in the phylum Arthropoda, class Insecta, order Hemiptera, family Pentatomidae.