When is a “Bug” Really a Bug?

Brown marmorated stink bug (Halyomorpha halys) Gary Bernon, USDA APHIS, Bugwood.org

Brown marmorated stink bug (Halyomorpha halys)
Gary Bernon, USDA APHIS, Bugwood.org

We may refer to any insect as a “bug”. In the pest control business, we often find ourselves doing the same thing. An insect taxonomist would have a fit because only a small group (40,000 species, to be exact) of insects can correctly be called bugs.

Only the insects in the suborder Heteroptera, part of the larger order Hemiptera, are known as “true bugs.” All other bugs are imposters. However, many refer to any insect in the larger order Hemiptera as a “bug”. All of the insects in the Heteroptera group share certain characteristics that other insects don’t, most importantly 3-4 segmented, piercing-sucking mouthparts. Many, but not all, of these bugs have distinctive front wings that have a leathery base with a membranous tip. Take a close look at a stink bug’s wings. Wings lie flat on the back at rest, forming an X. True bugs all have simple metamorphosis, which means there is not a larval stage. Immature bugs look like smaller versions of the adult bug, in shape if not always in color, and increase in size with each molt.

Bed Bugs ARE True Bugs!

Lightning bug Gerald J. Lenhard, Louisiana State University, Bugwood.org

Lightning bug
Gerald J. Lenhard, Louisiana State University, Bugwood.org

Many of the true bugs use their piercing mouth parts to suck juices from plants. Examples of true bugs in the Heteroptera suborder are lace bugs, stink bugs, seed bugs, squash bugs, assassin bugs, and finally… the very well-known wingless bed bugs. Bed bugs, and some assassin bugs, use their beak mouthparts to suck up blood rather than plant juice. You’ll notice that the most of the true bugs have the word “bug” as part of their common name. There are some exceptions though, for example, water striders and backswimmers are true bugs.

To confuse the issue even further, there are insects that are not in the Heteroptera group that have the word “bug” in their common names. For instance, ladybugs, June bugs, and lightning bugs all sound bug-like, but they are all beetles and are in a completely different order of insects. They are bugs imposters!