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What Makes a Bug a True Bug?

Stink bug
(Image: VPM)

What’s Bugging You?

When is a bug a true bug? Find out with entomologist Dr. Art Evans and VPM radio producer Steve Clark as they delve into the characteristics, classification, and proper spelling of the common names of true bugs.

Many people refer to almost any small multi-legged animal as a “bug,” but entomologists must necessarily be more precise. To them, a true bug refers only to members of Hemiptera, an order of insects that also includes cicadas, hoppers, and aphids. Like all insects, hemipterans have an external skeleton, three major body regions, and six legs. Hemipterans are distinguished from all other insects by a suite of characteristics that include hemimetabolous development and piercing- sucking mouthparts. Hemimetaboly, or gradual development, consists of an egg, nymph, and adult. Nymphs generally resemble the adults in form and habit, but lack wings. True bugs are placed in Heteroptera, a suborder distinguished from other hemipterans by having modified forewings with membranous wingtips and thick, leathery bases.

There are about 45,000 species of heteropterans worldwide. They occupy a diverse array of terrestrial and aquatic habitats. Most species sustain themselves by drawing fluids from nearly all parts of plants and fungi. Some suck the bodily fluids from insects and other arthropod prey. Others live as vertebrate parasites and suck blood from birds or mammals.

The common names of true bugs are always composed of two separate words and include bed bugs, kissing bugs, assassin bugs, stink bugs, and leaf-footed bugs. Consider the common name pillbug, a type of roly-poly.  Is it a true bug? No. Pillbugs aren’t even insects, but are terrestrial crustaceans. A similar naming scheme applies to flies, too. House fly and horse fly are both true flies and belong to the order Diptera. However, the common names “butterfly” and “dragonfly” are written as one word because these insects aren’t true flies. They are instead classified in the orders Lepidoptera and Odonata, respectively.

Common names for most insect species often vary regionally or don’t exist at all. Instead, scientists rely on a universally accepted system using scientific names. Correctly identifying a species is the first step towards locating information about its distribution and habits, as well as determining effective control measures should a species be of economic or medical importance.

To learn more about what’s in a name, check out this interesting story about how a gorgeous beetle that lives in the deserts of southeastern Arizona got its scientific name.