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Ichneumon Wasps

Ichneumonidae

Female ichneumon wasp with a black body, orange legs, and a long ovipositor on a plant stem

Often slender, with long antennae. Females use an egg-laying organ called an ovipositor to reach a host. Different species use different hosts. This photograph illustrates the wider ichneumon wasp family.

A large and varied family

Ichneumonidae includes many species, so this card describes a family rather than one Oregon species. Slender bodies and long antennae are common, but appearances vary widely.

What parasitoid means

The young develop by feeding on a host, eventually killing it. Different species use different hosts. A female uses her ovipositor, an egg-laying organ, to place eggs on, in, or near a suitable host.

Solitary describes social life

These wasps do not raise young in a queen-and-worker colony. Parasitoid describes their feeding strategy, so a wasp can be both solitary and a parasitoid.

Advice for sharing space with wasps

Learn More

Read the university identification and biology guide

Learn how parasitoid wasps develop

Photograph & license

Ichneumon wasp (Ichneumonidae sp) female by Charles J. Sharp, CC BY-SA 4.0. Resized; square crop for card display. Photographed in Oxfordshire, England.

The photograph illustrates this species or group; it was not necessarily taken in Oregon.

Solitary wasp

A solitary wasp has no colony of workers helping raise her young. A female may stock her own nest cells with food, or find a host for her developing offspring. Solitary describes social life; parasitoid describes a feeding strategy. A wasp can be both.

Social wasp

Social wasps share a nest and cooperate in raising young. In yellowjacket and paper wasp colonies, reproductive females lay eggs and workers help feed the brood and maintain the nest. They can defend that nest, so observing a forager is different from approaching a colony.

Non-native Social wasp

This is a social wasp introduced beyond its natural range. In this case the European paper wasp was introduced to North America from Europe, probably hidden in shipping materials. Non-native describes its origin, while social describes colony life.