Mud Dauber

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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.

Fast Facts

Color Body is shiny black, dark blue, or black with yellow markings.
Size Adults are about 1″ in length, females are larger than males.
Appearance These wasps are long and slender with a narrow, thread-like waist.

Diet

Adult mud daubers feed on plant nectar, honeydew, and body fluids from the spiders they capture.

Habitat & Nests

Carrying a ball of wet mud back to the nest site in her mandibles, the female mud wasp delicately crafts cells made to hold her eggs. Many short mud tubes, usually about 1″ long, are constructed side by side. Nests are usually built in sheltered sites protected from the rain, such as under eaves, porch ceilings, garages, sheds, barns and attics. The nests may also be found stuck to the walls of buildings or the sides of equipment. After the female constructs the chambers, she captures and paralyzes spiders to place in the cells as a larval food. An egg is laid in each cell, and it is sealed.

Mud Dauber control and nest removal - Batzner Pest Control in Wisconsin

Colonies & Life Cycle

Mud daubers are solitary wasps, meaning they are not social and do not live in colonies. However, more than one mud dauber nest may be found in suitable environments.

Mud daubers pass through four stages during their life cycle – egg, larvae, pupae and adult. Depending on the species, they complete one or two generations per year. In the spring, overwintering pupae develop into the adult. The new adult females will construct nests comprised of mud tubes of varying sizes. Each mud tube is provisioned with several spiders that the female mud dauber catches and paralyzes with her venom, preserving it until the offspring are ready to eat. The female mud dauber deposits an egg on each spider within each mud tube. This process continues until each chamber of the nest has been filled and sealed. The mud dauber queen then leaves the nest and doesn’t return.

The mud dauber larvae will hatch from the eggs and feed on the prey left behind by the female mud dauber. Then, the larvae will develop into pupae, a process that usually takes about three weeks. The pupae will spin a silk cocoon to overwinter until the following spring when they become adults. Once they have developed into adults, they will chew through the mud walls of the nest and emerge.

Stings & Damage

Because they are solitary wasps, mud daubers are not aggressive and do not defend their nest the way social wasps, like hornets and yellow jackets, do. In fact, mud daubers are very unlikely to sting, even when thoroughly disrupted. Although mud daubers generally aren’t dangerous or destructive, they can become a nuisance if they choose to build a nest under your eaves, on your porch, under your patio covering or in a garage or shed on your property. They are actually beneficial as they help control spiders.

Signs of Infestation

Finding a nest is the most common sign of a mud dauber infestation. If the nest has holes, it may indicate that the nest is inactive or old, as mud dauber wasps create holes when they leave the nest.

Prevention & Control

Mud Dauber Prevention
  • The most effective way to prevent a mud dauber infestation is to eliminate harborage sites by sealing cracks and holes in buildings.
  • It is also helpful to minimize the populations of their prey, including spiders, which reduces the chances of the wasp building around your home or property. Seal cracks and crevices where spiders hide and live and remove spider webs from corners.
  • You should also have old mud dauber nests removed because mud daubers will sometimes re-use an existing nest.
Mud Dauber Control

Control of these insects is not normally necessary since they pose little threat. Rather, mud daubers should be regarded as beneficial, since they remove and prey on many species of spiders. The mud nests can be scraped off and discarded at night if they are unwanted, or wasp and hornet aerosol sprays can be used to treat nests if desired.

Although mud daubers are not typically dangerous, their old nests are often taken over by other more dangerous wasp species. A licensed pest control professional should handle mud dauber nest removal.