Mud Dauber Guide

These earthen architects commonly build their nests near humans, but they're rarely aggressive

Mud Dauber Scientific classification

Also known as mud wasps or dirt daubers
Order: Hymenoptera
Family: Sphecidae
Genera: Chalybion, Sceliphron, Trypoxylon

Black Mud Dauber

If you've ever pondered the mystery of mud tubes and hollow balls appearing on your porch or in your garage, you've likely encountered one of the greatest insect homebuilders, the mud dauber.

These wasps are solitary, meaning that they don't swarm and they prefer to be left alone. Depending on the species, some build pipe-shaped nests while others build spherical nests. Mud daubers are usually more of an aesthetic nuisance than an actual problem. We'll take a look at how to identify the most common species, their unique diet and options for removing them.

DIY Wasp removal recommendations

For non aggressive wasps I've had great luck spraying the nests with this Spectracide wasp remover in the evening. For more aggressive wasps I also use this rediculous looking upper torso Beekeeping suit. It seems silly, but trust me, it's amazing.

Mud Dauber Identification

Mud Dauber Nest Image by Craig Talbert

The tubular or rounded mud nests are the key identifier. If you've observed flying insects tending to a mud nest near your home, you've encountered mud daubers. The insects themselves are ¾ to 1 inch in length with a very thin, long 'waist' called a petiole that connects the abdomen to the thorax. Coloration and nest architecture varies among species.

They might look like a terrifying hornet to the untrained eye, but the slim ‘waist’ is a key identification characteristic for these solitary wasps.

One of the more common species in the south western United States, and particularly in North Texas is the metallic blue mud dauber (Chalybion californicum). This dark-colored wasp shines iridescent blue in the light. However, they don't build any nests at all. Blue mud daubers move into the abandoned globular nests of the black and yellow mud dauber (Sceliphron caementarium). This common species is black with bright yellow markings on the legs, abdomen and thorax.

Tubular mud nests are constructed by the iridescent black pipe organ mud dauber (Trypoxylon politum). Cream-colored markings on the legs are an identifying marking that contrasts with the overall dark coloration. This species of mud dauber is distantly related from the other common mud daubers in North Texas. It is in the family Crabronidae, the 'square-headed wasps', while the others are Sphecid wasps.

Wasp Nest or Bird Nest?

It's possible to confuse a few bird nests with mud dauber homes. If you find a mud nest shaped like a cup, it's likely the home of a barn swallow family. These insect-eating birds are common in North Texas during the warm season, and they readily build their mud nests on porches.

Natural History

Mud Dauber Drinking Photo by David Hill

Mud daubers are actually dozens of species belonging to two scientific families within the order Hymenoptera: Sphecidae and Crabronidae. This makes them close relatives of ants, bees and other wasps.

Mud Dauber Nest For Raising Larvae

The three most common species in the south western United States hunt for spiders and then keep them paralyzed inside the nest until larvae are ready for a fresh meal. This unique method of food preservation is especially mind-blowing since the locally common blue mud dauber provisions with black widow spiders, the most venomous spider around.

Mud nests contain one to several cells, which serve as the wasp equivalent of a cradle for the young. Female wasps are the architects and builders of the nest. They build nests in locations that are protected from rain, which could mean they are interested in your porch or garage. As they construct each new cell inside the home, they place several captured and paralyzed spiders inside, lay an egg, and then seal the cell shut. The egg hatches into a wasp larvae that feeds on the dying spiders until it finally emerges as an adult. Cells contain up to 25 spiders, all of which are eventually eaten by the growing larvae as it nears pupation and adulthood.

Adult mud daubers feed on flower nectar. They spend days feeding and pollinating flowers, visiting muddy ponds for construction materials, and tending to young in the nest. They are considered parasites because they also spend a large portion of their time hunting for spiders to lay eggs on. Mud daubers are rare examples of insects that show parental care.

Do Mud Daubers Sting?

All mud daubers are solitary, meaning they don't live in swarms and they'd rather be alone. They are rarely aggressive but can sting if really bothered, such as during a nest removal. The sting is not as powerful as what you'd expect with hornets and yellowjackets. However, any wasp sting is dangerous to those who are allergic.

How To Remove Mud Dauber Nests

Mud Dauber Nest Photo by Katja Schulz

Considering that mud daubers are the top predator of black widows, think twice about removing them. Birds also feed on the wasp larvae, so nature may take care of the problem for you. If indeed they must go, here are some tips for a safe and effective removal.

At dusk or dawn, scrape off the mud nest with a shovel or similar tool. Mud daubers usually don't actively defend their nests, but these are the times when they are least active. If you have a headlamp with a red light, a nighttime removal would be even better. Insects can't see red light well, and they enter a period of rest after dark.
- If you look carefully when removing the nest, you might see the paralyzed spiders waiting inside.

Preventing Mud Daubers

Because mud daubers are more of a nuisance than a pest, homemade wasp deterrents should work fine.

Chili Deterrent: Boil 1-2 cups of chopped hot peppers in 2 cups of water for a few minutes. The resulting liquid can be sprayed on surfaces to keep wasps away.
Peppermint deterrent: Mix equal parts peppermint essential oil and water. This can be sprayed on surfaces or on skin as a general insect repellent.

Facts About Mud Daubers

Three airplane crashes have been blamed on mud dauber nests clogging sensitive equipment on aircraft.
Mud daubers are some of the few insects to provide parental care to their growing young.
It's common to find a few dozen paralyzed spiders within a softball-sized mud nest. The mother wasp places several in each cell for individual larvae to feed on, and then seals the cell shut with an egg and many spiders inside.
Mud daubers belong to two separate families in taxonomic classification, suggesting separate evolutionary paths for these two groups of wasp architects.
Mud daubers are the main predators of the black widow spider, helping to limit the abundance of the venomous spider.
Wrens, titmice and even woodpeckers feed on the larvae inside mud nests.
Female wasps don't begin nest construction until they have mated.