Iowa Insect Notes Mud Dauber Wasps Mud daubers are solitary wasps that construct small nests of mud in or around homes, sheds, and barns and under open structures, bridges and similar sites.
Several species exist in Iowa.
These wasps are long and slender with a narrow, thread-like waist. Some are a solid steel blue or black but others have additional yellow markings. This wasp group is named for the nests that are made from mud collected by the females. Mud is rolled into a ball, carried to the nest and molded into place with the wasp's mandibles. There are three different wasps that practice this behavior.