True Bugs are in the order Hemiptera and the only insects that are officially “bugs.” All other insects are insects, but not bugs. This can be confusing, especially because so many insects have the word “bug” in their common name. Ladybugs and lightening bugs, for instance — they’re insects, but not bugs. The Large Milkweed Bug (shown above), on the other hand, is an insect and a bug. Entomologists do love to have their fun!
The order Hemiptera also includes cicadas (suh-KAY-duhs), leafhoppers, aphids and other allied insects. Fossil evidence dates Hemiptera back at least 286 million years, from the Paleozoic era. It’s a large order with more than 40,000 known species around the world, including about 4,500 in the U.S. The name Hemiptera (he-MIP-ter-uh) is from the Greek words hemi, for half, and ptera, meaning wing. “Half wing” refers to the forewings of True Bugs, which are thickened on the half that attaches to the body, while the other half is membranous.
True bugs are a very diverse group. Most are terrestrial, but some are aquatic or semi-aquatic. Hemiptera includes plant feeders, predators and parasitic species. Some herbivorous species can be destructive, but most hemipterans are not and the predator species are beneficial.
Hemipterans range in size from minuscule to over four inches long. Their physical appearance is highly variable, but they are often either oval and flattened on top or elongate and round, like a cylinder. Coloration varies quite a lot, from dark-brown to bright patterns of red, green, blue and yellow. All hemipterans have a small head and compound eyes. They may have up to three light-sensing organs called ocelli (oh-CELL-ee).
Hemipterans have a tube-like proboscis (also referred to as a beak or rostrum) projecting from the front of their head that’s adapted for cutting into plant tissues and sucking the juices. Predator hemipterans hold prey with their front legs and suck body fluids. A few others are parasites. Most, however, are plant feeders. The proboscis (pro-BOSS-sis) is kept tucked horizontally under the body when it’s not being used.
The antennae may be short or long and are usually slender. In aquatic species they are usually short. Most hemipterans have two pair of wings, but some are wingless. The basal half of the forewings, particularly with the True Bugs, is thickened like the elytra¹ (EL-uh-truh) of beetles, but in this case they’re called hemielytra (“half wings”). As with the beetles, the hemielytra aren’t used for flight. The posterior part of the forewings, as well as the hind wings, on the other hand, are membranous and transparent.
Most hemipterans hold their wings flat on top of their backs, with the membranous portions overlapping. There’s a conspicuous area between the wings called the scutellum (skew-TELL-um). This is a segment of the thorax that’s enlarged and shaped like a triangle. (The thorax is the middle section of an insect’s body.) The crossed posterior part of the forewings sometimes has the visual effect of creating another rounded triangle at the end of the abdomen. You’ll quickly learn to spot these indicators, which, at a glance, distinguishes hemipterans from beetles.
Most have scent glands that emit an obnoxious-smelling fluid and some species should be handled with care, as they can deliver a very painful bite.
Look for them where they feed. For hemipterans who feed on plant matter, look on leaves and stems, or on the bark of trees. Also, look on the surface of water in ponds. In winter, look under boards, logs and the like.
Hemipterans undergo incomplete metamorphosis, which involves three stages: egg, nymph and adult. The life cycle of insects
Eggs may be laid just about anywhere: in plant tissue and crevices, on stems and leaves, and on the ground. Sometimes eggs are carried around on their father’s back, glued there by the female. Some females sit on their eggs until they hatch, then protect their hatched young for a time. The eggs hatch in about four weeks. The young, called nymphs (NIMF), look and act pretty much like their parents, but their coloring may be different and they are smaller and wingless. They go through several molts after hatching, with their wing “buds” getting bigger each time. With the final molt they are full-sized, sexually-mature adults. An adult is technically called an imago (em-AW-go). From egg to adult takes four to five weeks. Their life cycle is relatively long, with many species living a year. Most overwinter as adults.
Hemipterans are prey for fish, amphibians, birds, other insects, spiders, small mammals and other carnivorous animals.
¹Elytra are distinctively hardened forewings that provide a protective cover for thin, delicate, somewhat-transparent hind wings. Elytra meet in a neat line down the center of the back. Elytra are, for example, what make a lady beetle’s body look hardened.
*Top photo: Large Milkweed Bugs, Oncopeltus fasciatus. (David Hill / Flickr; cc by 2.0)