This group of wasps gets its common name from the fact that they construct their nest of mud. Mud daubers are considered nuisance pests and rarely sting.
Mud daubers are solitary wasps. They are not social and do not live in colonies. Mud daubers provision spiders for their larvae by paralyzing them with their venom and bringing them into their nests.
Female mud daubers construct nests of mud. Many short mud tubes, usually about 1″ long, are constructed side by side. They usually build their nests in a sheltered site, such as under eaves, porch ceilings, in garages and sheds left open, in barns and attics, etc. Nests typically exhibit round holes in them as the wasps emerge. This means the nest is probably old and inactive after springtime.
Mud daubers do not defend their nests. In fact, open pipe mud dauber stings are fairly rare. These insects are typically considered nuisance pests, and are actually beneficial as they help control spiders.