True bugs

The term bug is often used used to describe insects, spiders, centipedes and a whole range of other arthropods, but true bugs or Hemiptera actually only includes things like aphids and shield bugs. True bugs all have very unusual mouthparts. The mandibles have evolved into a spiky proboscus for sucking up liquids, usually plant sap or sometimes even blood. Some of the best known species, such as aphids, are significant pests of crops and gardens, while bed bugs are common human parasite. Most of the 75,000 species, however are not even noticed, and can even be benificial, like the damsel bug helping to keep the levels of some garden pests down.

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