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Mason & Potter Wasps

Eumeninae

Euodynerus mason wasp on damp ground

These caterpillar hunters use mud in their nests. Mason wasps often occupy existing cavities; potter wasps may build small mud pots. Each stocked cell shelters a developing young wasp. The photograph shows a mason wasp in the genus Euodynerus.

A group, not one species

Eumeninae is a subfamily containing many mason and potter wasps. The photograph is a representative mason wasp, not an identification guide to every member.

Two ways to build

Mason wasps generally reuse a cavity and divide it with mud. Potter wasps can build a complete little mud vessel. The young feed on stored prey, commonly caterpillars.

Independent mothers

Each female supplies her own brood cells rather than maintaining a worker colony. Nest shape and behavior can be useful clues alongside the wasp itself.

Advice for sharing space with wasps

Learn More

Read the university identification and biology guide

Photograph & license

Mason & Potter Wasps — Whitney Cranshaw, Colorado State University, Bugwood.org. CC BY 3.0 us. Resized and converted to WebP.

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.