Shield-shaped stink bugs (Pentatomidae) are fairly distinctive looking and smelling. Their common name comes from the presence of scent glands that open on their thorax, discharging pungent compounds over a wick-like surface near the bug’s hind legs. These compounds serve as a chemical deterrent for would-be predators, and also as an alarm for other stink bugs.
About a third of the 200 North American species of stink bugs are predaceous – they actively hunt and kill their prey. (The other two-thirds are plant feeders.) After spearing the prey with its piercing mouthpart, or beak, the stink bug injects digestive enzymes into its victim. These enzymes help liquefy tissues in the body of the prey and a muscular pump in the head of the stink bug enables the bug to suck nutrient rich liquid from its prey. Many predaceous stink bugs are major predators of webworms, tent caterpillars, Colorado Potato Beetles and a number of other insects that are considered garden pests. Unfortunately, non-pest species, such as the monarch caterpillar (see photo) are also subject to stink bug predation.
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