The English word "bug" is often used in a curious way to refer to any small creeping thing, especially when people see them inside their homes. Both ants and spiders are called bugs, even though spiders are actually arachnids.
What is truly curious, though, is that even calling an ant a bug is inaccurate. It‘s true that ants are insects, but they are not technically bugs.
True bugs are a suborder of insects within the order Hemiptera. True bugs are distinguished from other insects by the structure of their mouthparts and the way they feed.
True bugs are also unable to chew; their mouthparts are designed for sucking up their meals. Their mouthparts include a tube called a rostrum, often called a beak.
The rostrum is equipped with tiny needle-like structures for piercing called stylets. Connected to the rostrum is a pump, and muscles with which to operate the pump. The pump enables true bugs to inject secretions into their food and then to suck the food through their rostrum.
Most true bugs feed on plant sap. They access a plant‘s sap from a variety of sources, including the stems, roots, leaves, fruit and seeds of plants. A lot of true bugs are thought of as pests because they feed on human crops.
Stink bugs, for example, are true bugs and eat various fruits like tomatoes and peaches. Bedbugs and water striders would be other examples.
Of course, bedbugs don‘t eat, they feed on blood. Not all true bugs are herbivores, some feed on animals. Other true bugs feed on fellow insects.