Mud Dauber Wasps – A Quick Guide

The black and yellow mud dauber, Sceliphron caementarium, is also called the dirt dauber. They are found in North America and are around 1 inch (2.8 cm) in length. Here we answer some of the most asked questions about this species.

What do mud daubers prey on?

Mud daubers prey on spiders. They prey primarily on orb spiders, crab spiders, and jumping spiders. They grab spiders with their mandibles (claw-like mouthparts) and then sting the spider 3 times below the head. Mud daubers will often suck out the inside of the spider, or they will take them back to their nests whereby the paralyzed ( but not dead) spider will become food for wasp larva.

What do mud dauber nests look like?

They make nests out of mud. These nests constructed on walls and under roofs contain cylindrical tubes for cells. The wasp larva will develop in these cells surviving on spiders. The nest structures are often repurposed by birds the following season.

Mud dauber nest

Is the sting of the mud dauber painful?

The mud dauber has a sting that has very little impact on humans. Compared to other wasp species the sting is very mild. In his insect pain index, Justin Schmidt ranks the mud sting towards the bottom of the pain index, ranking it a 1 out of 4. He describes the sting as ‘Sharp with a flare of heat. Jalapeno cheese when you were expecting Havarti.’ Go here to see which wasps have the most painful stings.

In fact, it is very rare to ever be stung by a mud dauber. They use their stings to paralyze spiders that they prey upon, but they have very little venom. The Mud dauber wants the spider paralyzed, but not dead.

Mud Dauber Wasp
Michal Fuglevič

Where do mud daubers lay their eggs?

They seal their eggs into a mud cell with several paralyzed spiders. One egg is laid per cylindrical cell and up to 2 dozen spiders placed inside. The number of spiders depends on the size of the spiders. These paralyzed spiders will provide the food for the wasp larva as it develops into a fully formed wasp. The spiders are not killed immediately so as to prevent them from decaying.

Do mud daubers eat their prey alive?

They eat their prey alive. As the mud daubers’ sting paralyzes the spiders rather than killing them the spiders are alive while being consumed. The adult wasps suck out their insides, often through the spider’s mouth. The wasp larva eats the spiders saving the essential organs to last to keep the spiders alive for as long as possible to maintain the nutrient contents of their food.

Do mud dauber wasps go through metamorphoses?

The larva metamorphoses overwinter in mud cells. After consuming spiders as larva the mud dauber larva will enter the pupa phase of its development, cocooned over winter. If you see a distinctive mud dauber wasp nest over winter then it’s likely several mud daubers, one per cell, are developing in their pupa phase. On the arrival of spring, the full transformation will complete and a fully formed mud dauber wasp will chew its way out of the mud cell to begin the cycle over again.

Are males smaller than females?

As with most wasps, the male is smaller than the female and is unable to sting. The male will mate with the females shortly after emerging from their mud nests in spring. Once mated the males will die after completing their role. A female mud dauber will then build a nest, hunt for spiders, and lay their eggs. One exception is the male from the pipe organ mud dauber species which has been seen assisting in nest building and defending the nest.

How big are mud dauber wasps?

At about 1 inch (25cm) these are not the largest wasps, but not small either. They have very slender bodies and very noticeable thread-like bodies with a very thin and long section linking the thorax and abdomen.

Have mud daubers really been responsible for plane crashes?

Their nests have caused a number of plane crashes. An essential component found on a plane is a pitot tube. These provide essential data to airplane instruments by measuring the airflow when in flight. They don’t work so well if blocked by a mud dauber nest, however. At least 3 airline crashes have cited mud dauber nests as a contributor. Including Florida Commuter Airlines flight 65 in 1980. The 34 passengers and crew were killed when the plane crashed due to a blocked pitot tube.

Are mud daubers native to America?

Native to North America they spread to Europe in World war II. These wasps can be found all over North America and have since spread to many other parts of the world. The first sighting of them in Europe followed WWII when it is believed their nests were transported from North America when troops were deployed.

Do mud dauber wasps pollinate?

Mud dauber wasps do pollinate. Like almost all wasps the adult wasps consume large amount of nectar. By flying from flower to flower to get nectar they contribute to pollination. They also prey on spiders, principally to to feed to their larvae. Read more about wasps and pollination here.

(Source: Justin Schmidt – The Sting Factor)