Today’s factismal: Beetles represent about 40% of all insects and 25% of all animals.
If there’s one thing that drives entomologists (“people who study cut up things” – insect scientists) buggy, it is when someone calls a bug a beetle or a beetle a bug. That’s because the word “bug” (or “true bug” in entomologist-speak) and the word “beetle” each have specific meanings that help scientists understand what is being discussed.
Let’s start with the bugs. Not every insect is a bug; indeed, there are only about 80,000 known species of bugs out of some million or so species of insect. So one out of every twelve insects that you meet will be a true bug. But what a lot of true bugs you can see! There are aphids and bedbugs and water bugs and cicadas. The one thing that all true bugs have in common is a mouth that is made for sucking. Aphids and cicadas suck the juice out of plants (that’s why they are pests), water bugs suck the juice out of other bugs, and bed bugs suck the juice out of you!
Where true bugs are (relatively) rare, beetles are incredibly common. There are about 400,000 known species of beetle, with more being discovered every day (more on that later). Perhaps the best-known beetle is frequently called a bug: the ladybird beetle (aka, the lady bug). But the beetles includes other fascinating critters, such as the scarab, the weevil, the stag beetle, and the firefly. They live in environments ranging from Alaskan tundra to Amazonian rainforest, from dry desert to under the water of a lake, and from deepest forest to the middle of a city. And they are similarly varies in what they eat, with foods ranging from detritus (leaves and dung) to other insects to small animals, snail, or worms. About the only thing that all beetles have in common is that the front pair of wings has hardened into a shell that covers and protects the rear wings when the beetle is at rest.
But the most fascinating thing about all insects, be they true bug, beetle, or something else, is that we are still discovering new species! Some people think that there may be as many as one million more species of insect left to discover. But the entomologists can’t do it all themselves; they need your help. When you spot an unusual insect, post a picture of it on the Bug Guide website along with when and where you saw it. The folks there will help you classify the critter and let you know if you’ve seen something truly new: