Mud Dauber Wasps

Facts, Identification & Control

Scientific Name

Family Sphecidae & Crabronidae

Appearance

Mud dauber is a common name for wasps that make their brood nests with mud. There are many species of wasps referred to as mud daubers; some other common names are dirt daubers, organ-pipe wasps, mud wasps and potter wasps. Although their appearance varies greatly, mud daubers generally are from ½ to 1 inch long. Mud daubers are colored either completely black or blue metallic. Some species have yellow or greenish markings on the body. The body shape is typically “thread-waisted” with some mud daubers possessing an extremely long and thin, stretched out looking body segment located between the thorax and abdomen.

Behavior, Diet & Habits

Mud dauber wasps undergo complete metamorphosis, meaning they have four stages during their life cycle – egg, larvae (grub/worm-like), pupae (cocoon) and adult. Mud daubers are solitary insects even though in some suitable habitats more than one mud nest will be found. The shape of mud nests helps identify different groups of mud daubers. One nest shape appears as a group of cells that are cylinder-shaped and covered over with mud so it appears to be a smooth mud nest about 2 inches wide and about 4 inches long. Another, the organ pipe group, constructs a nest that looks like a series of tubes resembling the pipes on a pipe organ. Still another mud nest is constructed by the potter wasp that makes a nest resembling a small, clay pot. While most mud daubers make new nests for each generation, a few species will reuse old mud nests constructed by other mud daubers.

Mud daubers complete one or two generations per year, depending on the species. In the spring, the overwintering pupae (cocoon) develop into adults. The new adult females begin building a new nest and after completing the mud nest, begin to capture insects or spiders that are placed into each mud nest cell. Eggs are deposited on the prey within each cell, and the cell sealed with mud. The larvae that hatch from the eggs feed on the prey left by the adult wasp, and then change into the pupal stage (cocoon) that overwinters. Prey are stung and paralyzed, not killed, before being placed in the mud cell. This is crucial since dead prey would decompose and aren’t suitable nourishment for required larval development. The following spring, the pupae become adults, thus beginning the next generation of mud daubers. Adults feed on plant nectar, honeydew and the body fluids of the spiders and insects they capture. At least two species of mud daubers are especially important since they are reported to seek out and capture black widow spiders.

More Information

Mud daubers are actually very beneficial since they help reduce the numbers of some pest insects and spiders. Also, they are not likely to sting. However, it is never smart to approach their nests without exercising caution. If mud daubers become a nuisance and insecticide products are the answer, be sure to contact your pest management professional for their recommendations and assistance. If safety is not an issue, remove old, inactive nests. Since some species will reuse old nests, spiders or insect prey carcasses can become a food source for beetles that may contaminate fabrics or food. Scraping off the nest or using a strong stream of water from a garden hose works. In addition, anything done to seal harborage sites such as cracks and holes in buildings is helpful to reduce the prey population.