Mud daubers are solitary wasps that construct small nests of mud in or around homes. These wasps do not live in colonies, and there is no worker caste system. Adult wasps feed on plant nectar and honeydew, as well as the body fluids of insects and spiders they hunt and capture.

There are many species of mud dauber wasps, therefore they vary in colour. Often, they are black with a metallic sheen or with pale markings. Some are a solid steel blue or black. Some have additional yellow or green markings. In general, they have 6 legs, range between ½ and 1 inch in length, and have a long and slender shape, with a narrow, thread-like waist.

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. She constructs side-by-side mud tubes, each around 1 inch long. Nests are commonly found in chimneys, wall voids, attics, garages, barn walls, and under eaves, porches and decks. The appearance of the nest can vary based on the species:

  • The black and yellow mud dauber builds a series of cylindrical cells that are eventually plastered over with mud to form a smooth mud nest about the size of a fist.
  • The organ-pipe mud dauber, a more robust, black species, builds cylindrical tubes resembling pipe-organ pipes.
  • The metallic-blue wasp dauber does not build its own next. It uses the abandoned nests of other species of mud daubers.

If you come across a nest with round holes in it, the nest is likely old and inactive. The holes were created when the wasps emerged.

The life cycle of a mud dauber wasp colony begins when the overwinter pupae transform from a cocoon to an adult wasp and eat their way out of the nest. Once they emerge, they seek food and a mate. Posting mating, fertilized females will build a mud nest. Next, she captures several insects and spiders by using her stinger to inject a paralyzing venom. She places this live prey inside the mud tubes of her nest and deposits a single fertilized egg on top of each one. These insects and spiders will provide nourishment for the larvae that will hatch. Placing a dead insect or spider inside a cell will not provide the nutrients that an egg will need to develop. The cell is then sealed with mud. After the female wasp has finished a series of cells, she departs and does not return, nor does she guard her nest. The larvae that hatch from the eggs feed on the prey left by their mother. The larvae will next transition into the pupate phase and overwinter. They will emerge as adults in the following spring and continue the life cycle. While most often there is only a single generation each year, some species can have two.

While wasps usually evoke anxiety or fear because of their aggression and painful sting, solitary wasps, like the mud daubers are very unlikely to sting, even when provoked. They do not defend their nest the way social wasps do, and their stingers are used for paralyzing provisions for their new generations. They may sting if touched or if caught in clothing. Mud daubers, like paper wasps, yellow jackets and the bald-faced hornets, are beneficial to our environment, as well as people. They help to control pest insect populations, especially spiders, which can be a nuisance in your home. There are even a couple of mud dauber species that hunt and feed on black widow spiders (which are not common in Ontario).

Call 1 (800) 263-5055

Our Professional Team is Happy to Help!