Quick Guide to Mud Daubers
- Common Species in South Carolina: Black and yellow mud dauber (Sceliphron caementarium), blue mud dauber (Chalybion californicum), pipe organ mud dauber (Trypoxylon politum)
- Size: ½ inch to just over 1 inch in length
- Nesting Habits: Build mud nests in cracks, crevices, equipment openings, and plant stems
- Prey: Primarily spiders; some species hunt caterpillars, cockroaches, and other insects
- Behavior: Solitary, non-aggressive, rarely stings unless threatened
- Control Tips: Reduce spider habitats, seal entry points, manually remove nests, use insecticides only when necessary
Yellow and black mud dauber constructing a nest cell.
Photo: Howard Ensign Evans, Bugwood.org
Identifying Mud Daubers and Their Habits
Mud daubers are wasps that construct mud nests. There are three common species:
- Black and yellow mud dauber (Sceliphron caementarium)
- Blue mud dauber (Chalybion californicum)
- Pipe organ mud dauber (Trypoxylon politum)
They make a variety of nests ranging from elaborate structures (i.e., multiple tubes several inches long or small vase-like nests attached to plant stems) to merely ‘plastering’ up existing cracks or crevices in wood, stone, or masonry. Many mud daubers will fill holes in round openings in equipment and lawn furniture.
These wasps range from one-half inch in length to slightly more than one inch. They often have bright, metallic coloration and narrow, thread-like waists (petioles, the section between the mud dauber’s thorax and abdomen). Metamorphosis is complete, like other wasps and bees, and the immature wasps look like worms. Mud daubers are not social insects, although many females may use the same general area for nesting.
Organ pipe mud dauber nest cells.
Powell Smith, ©2007, Clemson University
Nest Construction and Life Cycle
The nests are brood chambers for raising their young, and are constructed and stocked by one female. Some species will repair old nests from previous seasons and reuse them. The nests are built divided into cells about one inch in length. They are usually stocked with spiders or other prey items, which the females’ stings and venom have immobilized.
The venom acts as a preservative, keeping the prey in proper condition to allow the larvae to develop. An egg is laid in each cell. When the egg hatches, the larvae feed on the provisioned prey. Upon completion of its development, the new wasp chews a hole in the cell wall and emerges. Many of our most common species, such as the yellow and black mud daubers and organ-pipe mud daubers, only use spiders for prey. Other species use a variety of insects, ranging from caterpillars to cockroaches, to stock the nests. Some related species that burrow into the ground catch large insects such as katydids and cicadas.
Are Mud Daubers Dangerous?
Mud daubers are not aggressive insects and rarely sting unless threatened or inadvertently contacted. Although the venom is primarily for paralyzing and preserving prey, it is painful. The yellow and black mud dauber was rated a 1 on a pain scale ranging from 1 (mild) to 4 (severe), which was the same rating as the red imported fire ant (Encyclopedia of Insects – Eds. Resh and Cardé).
Non-Chemical Mud Dauber Control
These insects are not pests, but some might describe them as nuisances. Mud daubers that stock their nests with caterpillars are beneficial insects. Since many consider spiders to be pests or at least nuisances, spider-collecting mud daubers could also be helpful. However, since spiders also reduce insect populations, this viewpoint is questionable. Habitat modification to reduce the attractiveness of an area to spiders is one means of reducing mud dauber activity. This would include caulking or plastering cracks where spiders could live or hide and regularly removing webs in corners and crevices. Household insecticides can also be used to reduce spider numbers. Manual removal of nests may discourage mud daubers and reduce later generations. Also, screening or caulking of any openings that may allow access into buildings will prevent nesting in these areas.
Chemical Control for Mud Daubers
Chemical control may be necessary if:
- There are known allergies to wasp or bee stings
- Large numbers of mud daubers are found in areas of high pedestrian traffic
Best Practices for Chemical Control
Insecticides registered in a specific area should be used according to label instructions. Many insecticide spray products are generally very effective for wasps and will quickly ‘knock down’ nesting wasps. They are not to be used to attempt to contact insects in flight. This type of insecticide often comes in containers that will spray a straight stream up to 20 feet. This way, one can treat the nests without exposing themselves to stings. Normally, when insects are less active, late evening or early morning are the times to use this type of treatment.
Wear long sleeves and pants when working with chemicals to apply to mud dauber nests or during any occasion.
References
Texas A&M AgriLife Extension. (n.d.) Mud Daubers. https://texasinsects.tamu.edu/mud-daubers/#:~:text=Common%20Name%3A%20Mud%20daubers,Order%3A%20Hymenoptera%3A%20Sphecidae
Originally published 03/08
