One predator can destroy many prey. For example, a lady beetle may eat several thousand aphids during its lifetime. Parasitic insects live on or in the bodies of other insects during at least one stage of their life cycle. The parasite gets food from its host and the host eventually dies. Most of these parasites are either flies or wasps that are parasitic as larvae and free living as adults.
Beneficial insects vary in importance in different areas.
Some may be more numerous in one area than another and population levels vary from year to year. Predators are more conspicuous than parasites and their importance is generally appreciated more. However, both are important in controlling harmful insect populations. They are dark brown in color, but are sometimes also marked with pink or red. Both nymphs and adults feed on the larvae and adults of most injurious insects except thrips, aphids, and spider mites.