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General Facts About Insects and Bugs

When is an insect not a bug? Do all insects bite? Which one is most poisonous? Experts answer 20 common questions.

  • Grades: 3–5, 6–8

The following questions were answered by zoo biologist Ellen Dierenfeld and entomologists John VanDyk and Steve Kutcher.

Q: Is there a difference between an insect and a bug?
A: Yes, there is a difference.

  • A bug is a certain type of insect. Some examples you might be familiar with are the boxelder bug, milkweed bug, assassin bug, and stink bug.
  • True bugs have a stylet (a mouth shaped like a straw) that they use to suck plant juices from plants. The assassin bugs use their stylets to suck blood from other insects.
  • The front wings of true bugs are thickened and colored near where they are attached to the insect's body, and are clearer and thinner towards the hind end of the wing. The hind wings are usually clear and tucked underneath the front wings.

Q: What is the largest insect?
A: In the book Beetles by Bernard Klaustnizer, there is a beetle called the South American longhorn beetle (Tytanus giganteus) that measures 25 cm! The heaviest insect is probably the African goliath beetle (Megasoma elephas), weighing up to 3.4 oz. And the longest insect is a huge stick insect (Pharnacia serritypes). The females can be over 36 cm in length!!

Q: Is there an insect that is worth money?
A: There are many, many insects that are worth money. For example, the pollination work done for free by insects would cost billions of dollars every year. Think about how much honey costs! Those bees are worth a lot of money. And insects like the praying mantis or ladybird beetle happily take care of eating harmful insects, saving money that could be spent on pesticides. There are also silk moths that produce silk, insects that produce shellac, and some insects that are canned and eaten! Make sure you don't let the reputation of a few harmful insects prevent you from noticing all the good ones.

Q: How do insects grow?
A: Insects have their skeletons on the outside, with their soft parts inside. That makes it hard for them to grow. Every time they want to become bigger, they have to break out of their skin and swell up to their new size before their new skin hardens. This is called molting. This means that once the insect is at its final size (adult form), it can't grow any bigger! So the butterflies and moths that you see flying around won't be any bigger tomorrow than they are today!

Q: What do insects eat?
A: Just about anything! There are so many different insects and each one may eat something different. Lots of them eat plants. Some of them eat other insects. Some of them eat blood (like mosquitoes). Nectar from plants is also a popular food. And many insects (like cockroaches or ants) will be happy to polish off that cookie you dropped on the floor!

Q: What's the most poisonous insect?
A: According to the University of Florida Book of Insect Records, the most poisonous insects are in the order Hymenoptera (wasp, bees, and ants) and the ones with the most toxic venom are certain harvester ants.

Q: What's the fastest insect?
A: Sphinx moths, or hawk moths, have been measured at 53 km/h. However, a horsefly (Hybomitra hinei wrighti) was recently clocked at 145 km/h! More research needs to be done in order to determine the fastest insect.

Q: Who discovered insects and where did the word "insect" come from?
A: I'm not sure anyone "discovered" insects, in the same way we think about discovering electricity or magnetic fields. But Plato was aware of insects, way back in the ancient Greek era. Insects are referred to in the Bible. Linnaeus started to catalog all the insects he could find. As for the name "insect," it is from Latin; the name was originally given to certain small animals, whose bodies appear cut in, or almost divided.

Q: What insect lives the longest?
A: A queen termite has been known to live 50 years and there are, of course, the 17-year locusts. Most bugs live less than a year and are seasonal. However, some wood beetles can emerge from wood where they live after as long as 40 years!! In one recorded case, the beetles came out of wood that had long ago been cut down and made into a bookshelf!

Q: What is the smallest insect?
A: I'm not sure what the smallest insect is (I had one here somewhere, but I can't seem to find it...) but the smallest insect eggs belong to a member of the family Tachinidae, a group of parasitic flies. These eggs are usually only 0.02 to 0.2 mm long.

Q: Do all insects bite?
A: There are lots of insects that don't bite people but do bite plants or other insects! Insects have different kinds of mouthparts. There are mouthparts for biting/chewing, strawlike mouthparts for sucking, and razor-sharp mouthparts for biting people. The vast majority of insects, however, do not bite people. They are content to eat plants, or nectar, or other insects.

Q: How many insects are in the world?
A: If you are talking about the number of different kinds of insects in the world, Erik J. van Nieukerken has made a scientific estimate that there are 1,017,018 species of insects in the world. Wow! That means you could spend your whole life looking at different kinds of insects and never see them all.

Q: Why do insects like light?
A: No one really knows. Most scientists think that bright lights confuse the insects'guidance systems so they can't fly straight any more.

Q: Why do insects have six legs instead of five or seven?
A: One can get around efficiently on six legs. It is harder if you use five, because that's an odd number. You would have one leg stuck in the air while the others are running, or going down all by itself. If you have a chance, watch an insect walking and pay attention to how it uses its legs. Put another way, think how much more difficult it would be for you to walk if you had three legs!

Q: Why do insects have three parts to their bodies?
A: That's a difficult question to answer. Maybe we can turn it around and ask, why don't you have three parts to your body? Or why don't you have a hard shell instead of soft skin? The answer is, no one knows. That is the way things have happened. We call animals with certain characteristics, like three main body parts, antennae, spiracles, etc., "insects." If they had eight legs and two main body parts, we would call them "spiders."

Q: Do insects have blood and do they bleed when they are hurt?
A: Insects have blood, but it's not like our blood. Our blood is red because it has hemoglobin, which is used to carry oxygen to where it is needed in the body. Insects get oxygen from a complex system of air tubes that connect to the outside through openings called spiracles. So instead of carrying oxygen, their blood carries nutrients from one part of the body to another. They do bleed when they are hurt, and their blood can clot so they can recover from minor wounds.

Q: Why do insects drown in water?
A: Not all insects drown in water. In fact, quite a few live there for at least part of their lives. Insects breathe through holes in the sides of their bodies. If they can't get air in through the holes, they will suffocate. That's why insects that are not specialized for living in water will die in water. But dragonfly nymphs, mosquito larvae, and water beetles all live in water quite happily!

Q: How do insects eat?
A: Insects eat by either chewing their food (like grasshoppers and caterpillars), or sucking it up (like aphids, stinkbugs and mosquitoes). Take a close look at the mouthparts of an insect sometime. There are lots of parts (I think I would get confused trying to eat with so many parts!).

Q: Which insects pinch?
A: Many insects that have biting/chewing mouthparts will nip you if you pick them up. Others, such as lady beetles, don't mind being picked up and will just fly away if they want to.

Q: Which insects live on trees?
A: There are so many different kinds of insects that live in, on, and under trees that there is a whole branch (no pun intended!) of entomology called forest entomology that deals with these insects. In many old-growth forests (and the rain forests) one tree is an entire ecosystem  —  like a separate world.

  • Subjects:
    Insects, Animal Structure and Movement, Animal Survival and Adaptation
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