Mud daubers build their nests high up on structures—you’ll usually see them near the roof of your house or under a porch roof. They also build nests in cave entrances, under bridges and in other places where they will be protected from rain.

Brick and stucco are especially prone to mud dauber nests because those materials help the nests stick. These insects have a reputation for clogging the exhaust pipes of lawn mowers and other seldom-used machinery.

Mud daubers are solitary insects, so if you find a nest, it’s almost certainly the nest of one wasp. Their nests take a few different shapes, most commonly appearing as either a series of organ pipe-shaped cylinders or round structures like clay pots. These nests contain numerous cells, each with a single egg inside.

Mud daubers are most active in warm weather. In tropical climates, they’re a prominent pest year-round. They are daytime pests, frequently spotted near puddles or saturated dirt, gathering mud to build their nests. These insects prefer clay mud, rolling it into tiny balls and carrying them with their long legs one at a time to the nest. The female builds the nest alone while the male guards it.

Mud daubers have stingers but they rarely use them on humans. They do not actively defend their nests and only sting humans when immediately threatened. Their stingers and venom—which is not dangerous to people unless they have a wasp allergy—are solely used to paralyze spiders, which they feed to their offspring in the nest.

Adult mud daubers feed on the nectar from plants, honeydew from other insects and sometimes on the spiders they hunt for their young. There are three stages in the mud dauber’s life before it reaches adulthood: egg, larvae and cocoon. In the summer and fall, females lay eggs in the nests. They paralyze spiders and seal them, still alive, in the cells of the nest for the eggs to feed on when they hatch.

After eating all of the spiders (as many as twenty-five in each cell), the young mud daubers enter their cocoon phase for the winter and emerge as adults the following spring. These wasps rarely reuse nests, so an infestation of mud daubers can quickly become an ugly site on the side of a house or building.

Since mud daubers don’t typically sting humans, they are primarily an aesthetic pest. Their nests can be unattractive and damaging to machinery.

The most obvious attraction for mud daubers is the mud they use to build their nests. Puddles, ponds and foundations with poor drainage create muddy conditions that are ideal for these insects. They’re also attracted by high populations of spiders. Unused or broken machinery and outdoor furniture are potential nesting sites and can bring mud daubers near your home.

Mud dauber nests can become unsightly blemishes on the outside of your home, shed or garage. They can also cause problems for people with allergies to insect bites. The easiest way to remove mud daubers from your home is to call the professionals at Aptive to begin a pest control plan.

You can take steps to prevent mud daubers from nesting on your house by following these tips:

1. Ensure that your home has proper drainage around its foundation to prevent mud from forming near your walls.

2. Follow Aptive’s spider control tips to remove the insects’ food source.

3. Regularly start and use machinery that’s stored outdoors to prevent nests in exhaust pipes and around engines.

4. Call your local Aptive branch to discuss a customized mud dauber control plan.