Organ pipe mud dauber nest

Organ pipe mud daubers are also an exceedingly docile species of wasp, and generally pleasant to have around, as they serve to keep spider populations down. Stings to humans are very rare, bordering on non-existent. They build nests in the shape of a cylindrical tube resembling an organ pipe or pan flute. Organ-pipe mud daubers build their very distinctive and elegant tubes on vertical or horizontal faces of walls, cliffs, bridges, overhangs and shelter caves or other structures.