Numerous airborne insect species that occasionally sting humans can be found in Massachusetts, and while most of these species are not inclined to inflict stings on humans, almost all are capable. Stinging insects in the state include yellow jackets, honey bees, paper wasps, hornets, and several species of solitary bees and wasps. Mud daubers are a lesser-known group of stinging insects that belong to the Sphecidae and Crabronidae families, and three species have been documented in Massachusetts including Sceliphron caementarium, Trypoxylon politum and Chalybion californicum. These three solitary wasp species are more commonly referred to as black and yellow mud daubers, organ-pipe mud daubers and blue mud daubers, respectively.

Both the black and yellow mud dauber and the organ-pipe mud dauber build their nests on the sides of houses, buildings and other structures. The blue-mud dauber is a parasitic wasp species that spends much of its time around puddles in order to quench its thirst. These wasps also use water to soften the nests that are inhabited by the other two mud dauber species. Doing this allows blue mud daubers to break into these nests in order to secure a safe shelter for themselves and their eggs, after, of course, they first eject the native eggs, making them parasitic house-guests.

In Massachusetts, the black and yellow mud dauber and the blue mud dauber species are particularly abundant in all areas of the state. These insects are aptly named, as the black and yellow species has a long black body with yellow marks, while the blue species possesses a blackish-blue exterior. Massachusetts homeowners often find both of these species near puddles, but the black and yellow species uses water in order to create and shape their mud-nests. A series of these nests are built side by side along a structure’s eaves, and other common nesting locations including garage ceilings, shed ceilings, roof overhangs, and numerous other locations on/in a home, building or other small structure.

Adult mud daubers catch spiders before transporting them into these nests in order to provide their developing offspring with food, but the adults do not reside within these unsightly nests, and they do not sting humans in an effort to defend their nests. However, these nests can become abundant and unsightly on homes and buildings, prompting most homeowners to scrape the nests off of their homes. Once the larvae mature into adulthood, they abandon their nursery nests, but they are known for inflicting painful stings when humans crowd the adult species or when a person accidentally leans against a specimen.

Mud daubers do not pose much of a threat to humans, as these insects are not generally aggressive and they only sting when they become significantly disturbed. Mud dauber venom is also used mainly to paralyze prey, making their venom relatively less potent than other wasp species’ venom. However, mud daubers may become a nuisance around a home where the insects often establish several nests. In some cases, numerous and always ugly mud dauber nests can annoy homeowners when the nests become established on their home. Before using a putty knife or similar tool to scrape the nests off of a home, it is important for residents to inspect these nests for any exit holes and/or mud cells that indicate the insect’s absence from the small nests.

Have you ever found what you believed to be a mud dauber nest on your property?