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Potter wasps are medium- to large-sized wasps, 9 to 20 mm (0.35 to 0.79 in) long. They are black with white, yellow, orange, or red markings. Potter wasp adults feed on flower nectar and collect small caterpillars to feed their brood. The caterpillars are paralyzed with the wasp's sting and piled into the brood cell-that is, the compartment in which the wasp larva develops. The female wasp then lays an egg on the stored caterpillars. The potter wasp larva consumes from 1 to 12 caterpillars as it grows. Potter wasps are important in the natural control of caterpillars.
Some species of potter wasps nest in the ground, in hollow plant stalks, in nail holes in wood, or in deserted bee and wasp nests. The nests of these species consist of a linear series of brood cells separated by mud partitions. Other species construct rounded, jug-shaped nests with narrow necks. These nests, which resemble miniature pottery, may be fastened at the bottom to twigs. Each female constructs one or more nests independently. She carries a droplet of water to a particular mud-collecting site and mixes it with dry clay earth, using her mandibles. The wasp's saliva may help to strengthen the dried mud. The architectural potter wasp collects wood fibers to cover the mud nest. Scientists believe that this behavior represents an intermediate stage in the development of constructing nests completely from paper, a behavior found in many other wasps.
Scientific classification: Potter wasps comprise the subfamily Eumeninae in the family Vespidae, which also contains hornets, yellowjackets, and paper wasps. Most species in North America that make pot-shaped nests belong to the genus Eumenes. The architectural potter wasp is Eumenes architectus.