The black and yellow mud dauber is a large (around 1 inch), docile, solitary wasp in the thread waisted wasp family (Sphecidae). As their common name hints at, females create nests out of mud, with up to 25 cylindrical cells in each. These are attached beneath rocks, under eaves, or on walls and rafters of picnic shelters, garages, and attics. Individual cells are typically packed with 6-15 (up to 40) paralyzed spiders …fresh food for the developing young. The egg is laid on one of the last spiders that goes in and then the cell is sealed up with a thick mud plug. The mother may also cover the entire cluster of cells. Take a peek at what the nest and life cycle look like.
Photo by Glenn Marangelo on 7/26/20 near St. Regis, MT.