Eggs, caterpillars and pupae are liked by birds, hedgehogs, moles, mice and predatory insects like ants and bugs, for example. Toads and beetles also eat caterpillars. Even some primitive people appreciate the nutritious animals.

Parasitic wasps and flies lay their eggs into or on the caterpillar. Their larvae feed on the organs of the caterpillar, killing it gradually. Because of this sometimes a wasp hatches from a butterfly’s pupa instead of the butterfly. Other caterpillars die before they can pupate because their organs are destroyed.
There are also parasites laying their eggs on leaves. The caterpillars swallow them when eating the leaf.
The number of parasites living in a single caterpillar can vary from one to 3,000, depending on the species of the parasites. Several species can live together in one caterpillar.
Since parasites effectively keep the number of caterpillars at a tolerable level, they are used to prevent agricultural pests when the farmers want to avoid poison.

Birds, bats, mice, moles, lizards and monkeys are the most important vertebrate animals attacking butterflies. Spiders, scorpions, predatory wasps and flies, dragon-flies and other insects menace adult butterflies as well as caterpillars. Mites and small flies live as parasites on adult butterflies.