What does it look like?
Stink bugs are part of the superfamily Pentatomidae, the third largest family of true bugs. “Penta” refers to their five-segmented antennae. Stink bugs are also called shield bugs because their thick wing covers look like a shield. Shield bugs do not belong to the Penta group.
Many stink bug species are brown or green but some are bright red and easy to spot. They are usually 1/4-inch to 3/4-inch long. Predacious stink bugs belong to the subfamily Asopinae, in which the first segment of the beak is fat and directed away from the head. Plant-sucking stink bugs have a thinner beak, pressed under the head.
Adult stink bugs have scent glands which open on the thorax (midsection). They get their name from the foul smelling compounds discharged near the hind legs. Immature stink bugs usually have scent glands which open on the abdomen.
Common names, colors and shield designs vary depending on the species. The green vegetable bug or green stink bug is light green with three pale spots on the edge of its thorax. The forest bug has a rounded head and bands of black and orange on the sides of its abdomen. Its legs are a reddish color.
The harlequin stink bug is about 1/8-inch long. It has a distinctive red and black pattern on its broad shield. The immature nymphs are very colorful.
The green soldier bug is 1/2-inch to 3/4-inch long. Its shield is bright green with yellow, orange or reddish edges. The nymph stage has an oval-shaped, green body with yellow and black markings.
The conspicuous stink bug is 1/4-inch to 5/8-inch long. Its shield is shiny blue-black with an orange band that may surround two black spots. The anchor bug has an unusual red-orange anchor shape on its shield
Where does it live?
Stink bugs are found throughout the world. Two-spotted stink bugs are found east of the Rocky Mountains in the United States and Canada. They live in fields and meadows. They are commonly seen on exposed plant surfaces such as stems and leaves. The green soldier bug is found throughout North America in crop fields, orchards, and gardens.
What does it eat?
Stink bugs are sap-suckers that feed on a wide variety of vegetation. About two-thirds of stink bug species are plant feeders (sometimes pests). Some species feed on both plants and animals or start life feeding on plants and later become predators. Some predatory stink bugs suck the juices of caterpillars and beetle larvae.
Green soldier bugs feed on plant juices from leaves, flowers, and fruits. Two-spotted stink bugs suck juices from weeds. Forest bugs feed on deciduous trees, like oaks and maples. Harlequin stink bugs attack cabbage, cauliflower, turnips and other vegetable crops.
How does it defend itself?
When they are disturbed they emit a strong defensive smell from their scent glands. The smell comes from cyanide compounds having a rancid almond scent. They have little need to hide because their foul smell keeps predators at a distance. The bad odor serves as a kind of chemical alarm for friends and a deterrent for enemies.
Their slow movement may help them avoid attention of predators. They do not bite, but if held tightly they may use piercing mouthparts to stab a hand. Their eggs may have spines for protection.
What stages of metamorphosis does it go through?
Stink bugs belong to the Order Hemiptera so they undergo incomplete metamorphosis. There is no pupal stage between the larval phase and the adult phase. The young nymphs resemble adults but have no wings.
Adults usually hibernate in winter and begin laying eggs in late spring or early summer. Females lay clusters of barrel-shaped eggs on plants. The clusters are stuck to each other and to flowers or leaves by a sticky substance. Nymphs feed throughout the summer.
Many nymphs are herbivores at first, but later become predators or omnivores. They molt to adults in late summer. One or two generations hatch each year. A few species guard the eggs until they hatch, and even take care of the young nymphs.
What special behavior does it exhibit?
Stink bugs move very slowly. Their slow movement, especially in the early morning, makes them easy to harvest, like a crop. In some cultures, stink bugs are used to add flavor to stews, or eaten for their own sake.
The predatory spined soldier bugs are often seen sitting on leaves or flowers with caterpillars impaled on their outstretched beaks.
How does this bug affect people?
The plant-sucking stink bugs include crop-damaging pests, such as the Southern Green Stink Bug and the Harlequin Bug. The green stink bug is a pest of fruit, vegetables, and grains. The green soldier bug damages fruit trees, soybeans, cotton, and corn.
About a third of North American stink bugs are beneficial predators of caterpillars and other harmful insects. The anchor bug, for example, preys on Mexican bean beetles and Japanese beetles.
Species with big shoulder spines prey on tent caterpillars and webworms. Their spines go right through the protective walls of the shelters to impale the prey. Some predacious stink bugs have enormous appetites for crop pests. An adult two-spotted stink bug can destroy 150 to 200 Colorado potato beetle larvae over the course of its life.
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