Many enemies: Geometrid moths are important prey for a wide variety of natural enemies. Moth larvae are attacked by insect-eating birds and spiders, moth pupae fall prey to shrews and predaceous beetles, and adult moths are taken by bats, birds and harvestmen (left image). In addition, parasitic wasps (parasitoids) attack moth eggs, larvae and pupae. There are also species of virus that attack moth larvae.
Eaten alive: An adult larval parasitoid will lay its egg inside the body of a moth larva. The egg produces a parasitoid larva that eats the still living moth larva from inside. When the parasitoid larva is fully grown, it emerges through the body wall of the moth larva, killing it in the process (right image).
Food for the young: Moth larvae are an important source of food for the chicks of many species of birds. This includes common bird species like the brambling, the great tit and the pied flycatcher. The chicks have a better chance of survival in years with many moth larvae because food is then plentiful. Hence, birds can rear large broods in moth outbreak years.
Did you know?
- By emerging in the autumn, adult moths are able to avoid predation from bird species that migrate south after the summer.
- Egg parasitoids are among the smallest insects that exist. They are small enough to allow an adult parasitoid to fit inside a moth egg that is only about a millimetre in diameter.
- Moth larvae are available only for few weeks during summer. It is important for insect-eating birds to time their reproduction to this period, so that they can feed their chicks with larvae.