True bugs – the good, the bad, the ugly

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Cicadas, leafhoppers, aphids, planthoppers, shield bugs, assassin bugs—these are some of the “true bugs” that live in your yard. You may not be able to name them, but they’re all around. Some are doing truly good work for you—eating pest insects and helping to pollinate as they move about your plants. Some can be soothing, even inspirational, like the songs of cicadas that announce the arrival of summertime. Water striders are fun to watch as they magically skate on a pond’s glassy surface. And, then, there are the others—critters that can smell up the house, stab you painfully, and leave your once-beautiful plants desiccated and just plain dead. Others are so ugly and frightening in appearance, you’d scream and flee if you could somehow see them a foot larger than they are. They’re a mixed group, this lot, but interesting to read about, as you’ll see.

True bugs are insects, and the only ones known officially as “bugs!” All other insects are insects, too, but they’re not bugs. That can be confusing, especially because many insects have the word bug in their common name. Ladybugs and lightning bugs, for example, are beetle “insects,” but not true bugs! On the other hand, the Large Milkweed Bug is an insect and a bug, To complicate things further, many true bugs, like aphids, are bugs without that word in their name. Got all that?! Entomologists do love to have their fun! 

So, what’s really behind that separation? Basically, just the fact that true bugs are classified separately because their mouthparts are designed for piercing and sucking, unlike most other insects. Of course, in common parlance, many of us will go on calling most insects “bugs.” But, just so you know.

Cute, smiling boy with a cicada standing on his nose.

Cicada’s don’t bite or sting. (OakleyOriginals / Flickr; cc by 2.0)



Background

Fossil evidence dates true bugs back at least 286 million years, to the Paleozoic Era. Their order, Hemiptera, is large, with around 82,000 species, including about 10,200 in North America. The name Hemiptera (hem-IP-ter-uh) is from the Greek words hemi, for half, and ptera, meaning wing. “Half-wing” refers to their forewings, which are thick on the half that attaches to the body, while the outer half is membranous.

Most true bugs are terrestrial, but some are aquatic or semi-aquatic. They include plant feeders, predators, and parasitic species. Some herbivorous species can be destructive, but most are not, and the predator species are particularly beneficial.

Physical description

True bugs range in size from minuscule to over 4-inches-long (10 cm). 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 beautiful patterns of bright red, green, blue, and yellow.

They have three body parts, like all other insects: head, thorax, abdomen.

All true bugs have a small head. It has with two compound eyes and, with some species, up to three light-sensing organs called ocelli (oh-CELL-ee). They have mouthparts (nothing like a human’s) and two antennae. The mouth is a tube-like proboscis (pro-BOSS-sis), also referred to as a beak or rostrum, which projects from the front of their head. It’s adapted for cutting into plant tissues and sucking the juices. Or, in the case of predator species, for stabbing their prey and sucking body fluids. A few true bugs are parasites. They keep their proboscis tucked horizontally under their body when it’s not in use.

The antennae may be short or long and are usually slender. In aquatic species, they are usually short. 

Squash Bug, Gonocerus acuteanagulatus. standing on a red leaf against a green background.

Squash Bug, Gonocerus acuteanagulatus, plant pest that gives off a foul odor if squashed.  (Katja Schulz; Flickr; cc by 2.0

The thorax, which is the midsection, has six legs attached and two pairs of wings. A few species are wingless. The front part of the forewings is thickened like the elytra¹ (EL-uh-truh) of beetles, but in this case are called hemielytra (half wings). The hemielytra aren’t used for flight. The back part of the forewings are membraneous and transparent. So are the hind wings, which are used for flight. All about beetles

Most true bugs hold their wings flat on top of their back, 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 crossed posterior part of the forewings sometimes has the visual effect of creating another rounded triangle at the end of the abdomen. When you spot these indicators, you’ll know you’re looking at a true bug.

The abdomen is the back part of the insect. It contains the heart and aorta, digestive tract, respiratory system, reproductive system, nerves and glands. Openings in the abdomen, called spiracles, allow for the exchange of air and carbon dioxide. More about insect anatomy

Most true bugs 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.

Life cycle
True bugs undergo incomplete metamorphosis, which involves three stages: egg, nymph and adult. More about the life cycle of insects

True bug females lay their eggs on plant 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 young for a time. 

Group of bright orange Large Milkweed Bug nymphs, Oncopeltus fasciatus, on milkweed plant.

Large Milkweed Bug nymphs, Oncopeltus fasciatus, on milkweed plant. Notice their tiny black wing buds. (Tara Allison / WW; cc by-nc-sa 3.0)

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’re smaller and wingless. They go through several molts after hatching, with their tiny wing “buds” getting bigger each time. With the final molt they are full-sized, sexually-mature adults. From egg to adult takes four to five weeks. Their life cycle is relatively long, as insects go, with many species living a year. Most true bugs overwinter as adults.

Habitat
Look for true bugs where they feed — on plants, where both plant-sucking species and predator species will be feeding. Look for water striders and Giant Water Bugs on the surface of water. In winter, look under boards, logs and the like, where they hibernate.

Predators
True bugs are prey for fish, amphibians, birds, other insects, spiders, small mammals and other carnivorous animals. They defend themselves by running away, hiding and releasing irritants and noxious odors.

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: Leafhopper (631372 / Pixabay; CO0)

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