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Black-and-yellow Mud Dauber

Sceliphron caementarium

Black-and-yellow mud dauber showing a long narrow waist

Its long, threadlike waist sets it apart from a yellowjacket. A female builds mud cells and fills them with spiders for her young. There is no defensive worker colony, though handling or trapping a wasp against skin can provoke a sting.

Building with mud

A female carries small balls of mud to a dry, sheltered spot and shapes them into brood cells. Eaves and outbuildings can offer suitable cover.

A pantry for one larva

She paralyzes spiders, stocks a cell, lays an egg, and seals it. The larva eats the stored spiders, then develops into a pupa before becoming an adult.

No worker colony

Several mud cells do not mean a yellowjacket-style colony is present. Each female provisions her own offspring. Avoid handling the wasp or trapping it against your skin.

Advice for sharing space with wasps

Learn More

Read the university identification and biology guide

Photograph & license

Black-and-yellow Mud Dauber — Kevin Krebs. CC BY 4.0. 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.