Shield bugs kill caterpillars
Pests have their own ‘pests’ in the form of predators and parasites. Predators are usually large and fast moving, killing and eating the pest species. Obvious examples are birds, bats, hedgehogs, field mice, frogs and foxes, which dispose of considerable numbers of insects and other pests.
Less well-known are the insect predators, which include ladybirds, lacewings, ground beetles, hoverflies, capsid bugs, spiders and earwigs. Most of these live off greenflies, suckers, leaf-hoppers and red spider mites.
Parasites are usually smaller than the insect they parasitise, and the pest is usually kept alive for some time before eventually dying. Many kinds of tiny flies, wasps and midges parasitise the eggs and larvae of pest species, especially greenflies and caterpillars.
Pests are attacked by diseases that play an important role in limiting their populations. For example, myxomatosis disease greatly reduced the rabbit population, although rabbit numbers have recovered considerably.