When most people see an insect, their response is “ew, a bug.” But the term “bug” is actually incorrectly used if talking about any insect besides Hemiptera. These insects, which fall into about 40,000 species, are the “true bugs” of the insect world. Although “bug” is used for any small creepy crawly wandering across the kitchen floor, scientifically a bug is just a subsection of the hexapodal arthropods. Hemipterans have a few major distinguishing characteristics that make them different from other insects.
First, they have incomplete metamorphosis. They are the last insects in the phylogenetic tree to have incomplete metamorphosis, the next major order being beetles. This means that instead of having 4 distinct life stages (egg, larva, pupa, adult), hemipterans hatch right out of the egg often looking like smaller versions of the adult form. As they mature, they shed their hard exoskeleton to grow larger. Each successive molt is called an instar, and the age of hemipterans can be determined by an expert entomologist by studying the morphology of instars.
The name “hemiptera” means literally “half wing.” They have acquired this name because of an interesting characteristic on their fore wings. If you recall, a beetle’s forewings are hardened into an elytrum, which protects the hind wings folded underneath. True bugs have something similar to that, in that their forewings are only half membranous at the ends (and the hind wings are completely membranous). A picture is included below for convenience. Note the hardening at the base of the forewing.
One major way to distinguish insects in the order Hemiptera is by what is called the scutellum. This is a triangle patch on the abdomen right below the thorax. This is created by the way the wings are folded across the back, and is an easy way to quickly identify Hemipterans. In the image below, the scutellum is the black triangle below the thoracic segment.
All insects in the order Hemiptera have similar mouthparts. These mouthparts are modified to pierce and suck. Many times, the modified beak is used to stab into plants and suck out plant juices, but there are some insects such as assassin bugs that will stab into humans to drink their blood. Because of this possibility for blood to blood contact, a parasite has developed that can travel through these insects from human to human. The disease is called Chagas disease, and mostly affects poverty stricken areas in the Americas. More information about the symptoms and epidemiology of Chagas disease can be found here.
Bed bugs are another pest that preys on human blood. Although they are annoying, bed bugs are not known to transmit any human diseases. However, they can be quite difficult pests to get rid of as they usually produce large numbers of offspring and can live for up to fifteen months without eating.
Many members of the order Hemiptera are crop pests, especially from the family Miridae, or plant bugs, like the Adelphocoris plant bugs which harm alfalfa crops. From the family Tingidae, lace bugs suck juices from leaves of daisies, and birch trees. Green stinkbugs from the family Pentatomidae are significant pests, preying on many major crops such as apple, peach, and orange trees, as well as soybean, cotton, tomato, corn, and bean plants.
In addition to the land insects, many of the true bugs in the order Hemiptera are aquatic for all or at least most of their lives. Species such as the water boatmen (Corixidae), backswimmers (Notonectidae), giant water bugs (Belostomatidae), and the waterscorpions (Nepidae) have all developed adaptations to spend most of their lives underwater.
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I never knew that a “bug” is different from an insect. I always just thought it was a colloquial way of saying insect, very interesting! I am assuming from what I read from you post that ticks fall into this family of bug, and if so I’m not a fan (lol). Lyme’s disease sucks! This was a very well written and informative blog post. Your pictures were very well placed and helpful when reading along. Great job!
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This post was so interesting! I like how you started off this post because that’s always my response when I see of hear of bugs. Also I had no idea that a bug is not the same thing as an insect. I, like Ashlyn, always just thought we called all insects “bugs”. It’s amazing to me how much you know about insects and I’ve learned so much from these posts.
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It’s interesting to note that bugs and insects actually have distinct qualities that make them classified as one or the other. I always just thought “bug” and “insect” were synonymous, in which the term bug was more commonly used while insect is used in scientific terms. I also did not know that bugs other than bed bugs can pierce into human skin- that scares me! I’ve always had a fear of bed bugs when I go to hotels. Do you ever check for them? With your love for bugs, I’m sure you would actually be intrigued by them whereas I would scream.