Mud Daubers, AKA Dirt Daubers, Dirt Diggers, Dirt Dobbers, Dirt Divers or Mud Wasps, are common wasps found throughout the Greater Sacramento area. You know those blobs of dried mud that somehow find their way under the eaves of buildings? Thank your neighborhood mud daubers for that.
These dark and elegant wasps shouldn’t be confused with their more aggressive relatives, the paper wasps. They are wasps and do sting; however, they are solitary in nature and rarely sting people, even in defense of their nests. If you do come across a mud dauber nest, don’t bother it. Contact Pro Active Pest Control in the removal of mud daubers and their nests.
Mud Dauber Identification
Blue-black in color with iridescent blue wings
Large (1/2”–1”+) and very active during the day
Thread-waisted with an exaggerated narrow waist between their thorax and abdomen
Active during the warmer months of the year (April-October)
Most easily identified by their distinct mud nests that typically are supported by a male/female pair
Mud dauber nests are time-consuming projects. Their first choice is to reuse an existing nest (which if placed in a good, protective spot can last many years), or to build a new nest out of mud. The nests are composed of multiple, one-quarter inch tubes that can be increased over time. Each tube is stuffed with of spider snacks (i.e. five or six smaller spiders), after which the female laying an egg inside, and seals off the tube with more mud.
Adult mud daubers eat nectar from flowers, but spiders are the principle food choice for mud dauber larvae. Female adult mud daubers seek out, ambush and sting specific spiders. In the Greater Sacramento area, these tend to be black and brown widow spiders. The venom from a mud dauber’s sting doesn’t kill the spider but paralyzes and preserves it so that it can be transported and stored for later consumption by the hatched larva. While the female is out hunting, her male partner guards the nest from potential predators, such as parasites.
After hatching, mud daubers stay in their individual tubes throughout the cooler months. They then emerge in the spring as adults, ready to breed and prey on more spiders. Whether or not mud daubers are beneficial pests depends upon your individual situation. Mud daubers again aren’t aggressive, but they still can pose a potential threat to anyone allergic to wasp stings. They do control local spider populations, sometimes to the benefit of the insect populations that are controlled by the spiders.
Mud dauber nests can pose problems from being merely unsightly, to harming tools and machinery they attach to. They also invite other more harmful pests, such as more dangerous wasp species and bees, who make use of their abandoned nests.
To manage and deter mud daubers from taking up residence at your home or business, be sure to control your spider population through regular pest control. Remember, you want to decrease both potential shelters and food sources for mud daubers. Mud daubers nests should be removed by a pest management professional, such as Pro Active Pest Control.