Insect predators, in the immature and often adult stages, feed directly on their prey, killing them immediately. Other insects parasitize their hosts by depositing eggs on or in them. Larvae emerging from the eggs typically develop within and emerge from the host. Parasitized insects usually continue to feed for a time before they die. Examples of insect natural enemies which parasitize pest species include many tiny wasps and flies.
Natural enemies are an important component of integrated pest management programs.
For example, in home flower and vegetable gardens adult and immature lady beetles can quickly reduce a population of aphids thus eliminating the need to apply a chemical spray. Suppression of pests by beneficial insects alone, however, can be variable. When pest populations are large and there is enough food and the proper habitat to support the growth and reproduction of natural enemies, the impact of beneficials on pest populations can be greater. When pest populations are low, beneficials will search elsewhere for a food source. Beneficial insects tend not to recover as quickly from exposure to insecticides as pest species do.