Bugs or Insects? Whats the Difference?

They seem to be everywhere – creeping and crawling and flying around. Sometimes we call them bugs and sometimes we call them insects. But how do we know the difference between bugs and insects? Bug is a general term referring to several classifications of animals. (Yes, insects and bugs are animals.) They belong to a class called Arthropods. The word bug is not a scientific classification. It’s more like a nickname given to some Arthropods. There are four classes within Arthropods as shown in the table below. We often refer to three of the classes as bugs. We seldom call Crustacea bugs. Somehow a shrimp or lobster doesn’t seem like a bug!

These classifications help us divide the members of the animal kingdom into groups so we can see how they are alike and different. It helps us make sense of the many animals in our world. Insects have their own classification called Insecta. These animals have three parts to their bodies – head, thorax, and abdomen. They also have three pairs of legs and a pair of antennae. Sometimes they have wings. Notice these parts on the picture of the ant.

The other classes that we call bugs are different from insects. Arachnida have two parts to their body – a cephalathorax (a head and thorax combined) and an abdomen. They have four pairs of legs, no antennae and no wings. You’ll never see a flying arachnida.

Notice these parts on the picture of the tarantula. The third class of arthropods that we call bugs is Myriapoda. These bugs have a head and a trunk. They have many pairs of legs, one pair of antennae and no wings. Notice these parts on the picture of the centipede.

Now that you know the difference between the three classes of bugs, you can identify them when you see them and begin to think like a scientist as you make sense of our world filled with bugs.