My son was corrected in school yesterday when he referred to a cockroach as a bug. The teacher said that cockroaches aren’t bugs, that only certain insects can correctly be called bugs. Is that true and what difference does it make anyway?

S.V., Ayer, MA

Well, it probably only makes a real difference to an entomologist or to a science teacher who is trying to teach insect classification. The teacher is right, there is only one suborder, Heteroptera, that we refer to as “true bugs.” All of the insects in this suborder share certain characteristics that other insects do not possess, most importantly a particular style of piercing-sucking mouthparts. Winged true bugs also have distinctive front wings with a thickened base and a membranous tip. They all have simple metamorphosis which means there is no larval stage. Immature bugs look like smaller versions of the adult bug.

What’s In a Name?

Any insect that is classified as a true bug in the Heteroptera suborder can correctly be called a bug, and any insect that is not in the Heteroptera group is not officially a bug. Examples of true bugs are lace bugs, leaf bugs, stink bugs, seed bugs, squash bugs, and finally…bed bugs. But to confuse the issue, there are other insects in other groups that also have the word “bug” in their name. For instance, ladybugs, June bugs, and lightning bugs all sound bug-like, but they are beetles and imposters.

Aren’t Bugs the Cute Versions of Scary Insects?

Even in our profession, sometimes it’s just easier, and more fun, to refer to any insect as a bug. In my mind, “bugs” tend to be seen as the less threatening, more fun insects. Maybe that’s because bug is a term that children use and it’s a term that we adults use around children. Bugs, after all, are the subjects of children’s storybooks. Ladybugs are our friends.

Bugs may be considered cute today but it’s believed that the origin of the word came from the Welsh word bwg, meaning “hobgoblin” or “spectre.”  Apparently Shakespeare even used the word to refer to “bogeymen” or “malevolent spirits.” It’s possible that the nighttime spirits referred to were actually bed bugs, the original “bugs.” Perhaps then all the close insect relatives of bed bugs also came to be known as bugs, and the suborder of true bugs was born. Or, maybe not.