Mud Dauber Wasp

Introduction

This group of wasps gets its common name from the fact that they construct their nest of mud. They are typically nuisance pests. Mud daubers are found throughout the United States.

Recognition

Adults mostly about 1/2-1+” (12-25+ mm) long, slender. Color usually black, may have pale markings or a metallic luster. Thorax with pronotum collarlike. Wings clear or dark; front wing with 1 or 3 submarginal cells. Abdomen either very slender or petiolate (stalked).

Similar Groups

1. 1. Other sphecid wasps (Sphecidae) do not make mud nests and either with more than 1 submarginal cell in front wing and eyes not notched on inner margin or 1 tooth on front tarsal claws, middle tibia with 1 apical spur, and usually both recurrent veins meet 2nd submarginal cell of front wing.
   2. Paper (Polistes spp.) and some potter wasps (Eumenes spp.) with pronotum in lateral view almost triangular, extending to tegulae (structure at base of front wing) or nearly so, 3 submarginal cells in front wing, and 1st abdominal segment conical, not stalklike.

Representative Species

1. 1. Organpipe mud daubers; subfamily Trypoxyloninae. Mostly about 1/2″ (13 mm) long; color black; head with inner margins of eyes notched; front wing with 1 submarginal cell, marginal cell pointed apically; and make long (up to 8+”/20+ cm) tubular mud nests provisioned with spiders.
   2. Black-and-yellow mud dauber, Sceliphron caementarium (Drury); subfamily Sphecinae. About 1/2-1 1/8″ (14-28 mm) long; color dull black with antennal bases, prothoracic collar, scutellum, portion of metathorax, petiole, and parts of legs bright yellow; 1 tooth on front tarsal claws, middle tibia with 2 apical spurs; front wing with 3 submarginal cells, both recurrent veins meet 2nd submarginal cell; abdomen stalked at base, petiole long; and nests are comprised of several short tubular mud cells clustered side-by-side and plastered over with mud, which are provisioned with spiders
   3. Blue mud dauber, Chalybion californicum (Saussure); subfamily Sphecinae. About 1/2-3/4″ (12-18 mm) long; color metallic blue, blue-green, or blackish with bluish wings; 1 tooth on front tarsal claws, middle tibia with 2 apical spurs; front wing with 3 submarginal cells, both recurrent veins meet 2nd submarginal cell; abdomen stalked at base, petiole moderate in length; and does not make a nest of its own but instead is dependent on those of black-and-yellow mud dauber (S. caementarium), discarding the original nest contents, then adding its own spiders and eggs.

Biology

Mud daubers are solitary wasps, they are not social and do not live in colonies. The Sphecinae mud daubers over winter as full-grown larvae, pupate in the spring, and emerge shortly thereafter. Females construct nests of mud. Many short mud tubes/cells, usually about 1″ (25 mm) long, are constructed side-by-side. Each cell is provisioned with several spiders which she has paralyzed with her venom, with the first spider in having an egg deposited on it. Eventually this mass of tubes is about 3-4″ (7.6- 10 cm) in diameter and is entirely plastered over with mud. The female then selects another site and starts over. A larva can complete its development in about 3 weeks, then spins a silken cocoon but does not pupate until the following spring. Females typically provision their cells with only one kind or group of spiders.

Mud daubers do not defend their nests, and only rarely sting.

Habits

Mud daubers typically select a sheltered site to build their mud tubes. Favorite sites include under eaves, porch ceilings, in garages and sheds left open, in barns, protected building walls, in attics, etc.

Nests typically exhibit round holes in them as the wasps emerge. This means the nest is probably old and inactive after springtime.

Pest Control Naples

Mud daubers are beneficial insects and help control spiders. If the nest is located near human activity, then control is warranted. First, if the female is in the tube, simply wait a few minutes for her to leave, or treat her with a short burst of an appropriately labeled aerosol pyrethrin/pyrethroid pesticide; use of a water-based pesticide formulation will create a muddy mess. Since mud daubers are reluctant to sting and do not aggressively defend their nests, their mud nests can simply be removed with a putty knife or scraper; sweep up the dislodged mud nest. Any mud tube nests should be removed because they may be parasitized by cuckoo wasps (family Chrysididae) during construction, or abandoned nests may be adopted and rehabbed by leafcutting bees (family Megachilidae). Activity can be discouraged in a given area by the application of a microencapsulated or wettable powder pyrethroid formulation.