Four-Toothed Mason Wasp (Monobia quadridens)
Detailing the physical features, habits, territorial reach and other identifying qualities of the Four-Toothed Mason Wasp.
Updated: 5/23/2018; Authored By Staff Writer; Content ©www.InsectIdentification.org
Sometimes mistaken for the Bald-Faced Hornet, the Four-Toothed Mason Wasp is not nearly as social.
The solitary Four-Toothed Mason Wasp is a beneficial insect to have in the garden, just like its doppelganger, the Bald-Faced Hornet. The Mason Wasp reduces the number of leaf-rolling caterpillars by using them as food for their newly hatched larvae. Shiny black, hairless bodies have white, angled 'shoulder' marks. A thin white band before the waist and a thicker white band after the waist contrast sharply with the rest of the body. The black wings have a metallic luster to them, reflecting shades of purple and blue.
A female will create a nest in an abandoned hole created by a Carpenter Bee, Mud Dauber, or ground nests from another species of bee, or she uses hollow tubes found in the area like plants stems, pipes, or hollowed-out tree branches. Once the location is determined, she builds cells in it where she will lay her fertilized eggs. She then begins to hunt a variety of moth and cutworm caterpillars in order to sting them, permanently paralyzing them. She brings them back to her nest and puts a few in each cell with an egg, and then plugs the cell up with mud. Hatched larvae begin feeding on the living caterpillars in their cells. After a few days of growing, a larva will pupate in the cell. Some late-season larvae will overwinter as pupae. After pupating, it will eventually chew through the mud cell and free itself. Adults drink flower nectar. They are most active in the summer and usually found in gardens and meadows.