Dr. Toby Schuh, an entomologist at the American Museum of Natural History, says:
You might say that any creature that flies, crawls, or buzzes is a bug.
This is okay for everyday conversation, but entomologists only say “bug”
when talking about the group heteroptera also known as “true bugs.”
As you explore the world of entomology, keep in mind:
- All insects have six-legs, three body sections (head, thorax, abdomen),
and usually have two pairs of wings.
- Insects include flies, mosquitoes, bees, crickets, dragon flies, beetles,
and butterflies, and many others.
- Spiders, ticks, and centipedes are not insects. For one thing, they
have more than six legs.
True bugs all 40,000 species of them – share these features:
- Special mouthparts for feeding on the “juice” of green
plants, or in some cases, animals.
- Saliva that contains chemicals called enzymes that break down solid
food into liquid.
- Stink glands that provide defense, help attract bugs of the same
species, and support interspecies communication.
When they hatch, true bugs look like smaller versions of the adult form;
they do not go through complete metamorphosis.