What is a bug?

People often use the word ‘bugs’ as a general term for insects. Some people even think of spiders as bugs. But in scientific literature the word bug has a very special meaning, and no, I’m not talking about secret electronic listening devices.

Staring into the face of a cicada. Cicadas are sap-sucking insects that qualify as bugs.

When you’re talking about insects, the word bug refers specifically to members of the order Hemiptera. Hemiptera is a large group of insects with specialised sucking mouthparts. If an insect falls into this group it is sometimes referred to as a true bug.

There are tens of thousands of different types of insects in Hemiptera. They include — but aren’t restricted to — cicadas, aphids, leafhoppers, treehoppers and shield bugs. Because so many of them use their mouthparts to suck sap from plants, they can become a bit of a nuisance in the garden if their numbers get out of control. Thankfully there are plenty of critters which eat bugs, including birds and other types of insects.

Some other examples of bugs

1: Lantana Treehoppers are another type of bug. This photo is of an adult.  2: Lantana Treehopper nymph

1: Citrus Bug  2: Close-up shot showing the Citrus Bug’s sucking mouthpart

1: Mealybug  2: Passion Vine Hopper

1: Harlequin Bugs  2: Leafhopper

1: Assassin Bug. This insect doesn’t use its mouthparts to suck the juices out of a plant. Instead they’re used to suck the juices out of other insects.  2: Close-up detail of the head of an Assassin Bug. That thing hanging down like an elephant’s trunk is the specialised sucking mouthpart.

1: Underneath view of a Cicada. The long, sucking mouthparts are easily seen extending across the middle of this photo  2: Although mosquitos have mouthparts capable of piercing and sucking, they do NOT fall into the group known as ‘true bugs’.

So now you know: a bug is an insect from the order Hemiptera. Does this mean it’s a bad thing to refer to other creepy-crawlies as bugs? I don’t think so. The word ‘bug’ has such common use as a term to describe all sorts of critters, including other types of insects, spiders and centipedes, that it would be impossible to be so strict about it even if you wanted to. And if I tell my friends I’ve been out with the camera taking ‘bug shots’ I’m sure they don’t assume I’m limiting my subjects to Hemiptera. Like many other words, ‘bug’ has different levels of meaning, and so I personally don’t think it’s a big deal.

So, does this mean that all insects with sucking mouthparts are true bugs?

Nope. Not all of them. There are other insects, like mosquitos for example, which fall into a different group.

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