Paper wasp

Paper wasps are 3/4 inch to 1 inch (2-2.5 cm)-long wasps that gather fibers from dead wood and plant stems, which they mix with saliva, and use to construct water-resistant nests that appear to be made of gray or brown papery material. Paper wasps are also sometimes called umbrella wasps, due to the distinctive design of their nests.

Paper wasps are members of the family Vespidae (which also includes yellowjackets and hornets), and belong to the subfamily Polistinae, but often colloquially includes members of the subfamilies Vespinae and Stenogastrinae, which also make nests out of paper. Twenty-two species of polistine paper wasps have been identified in North America and approximately 700 species have been identified world-wide. Most paper wasps live in the western hemisphere sub-tropics.

The nests of most true paper wasps are characterized by having open combs with cells for brood rearing, and a petiole, or constricted stalk, that anchors the nest (see image, right). Paper wasps secrete a chemical which repels ants, which they spread around the base of the anchor to prevent the loss of eggs or brood.

Most social wasps of the family Vespidae make nests from paper; although some tropical wasp species, such as Liostenogaster flavolineata, use mud. A small group of eusocial crabronid wasps, of the genus Microstigmus (the only wasps outside the family Vespidae), also construct nests out of chewed plant fibers, though the nest consistency is quite different from those of true paper wasps, due to the absence of wood fibers, and the use of silk to bind the fibers.

Unlike yellowjackets and hornets, which can be very defensive, paper wasps will generally only attack if the nest is threatened.citation needed] Since their territoriality can lead to attacks on persons, and because their stings are quite painful and can produce a potentially fatal anaphylactic reaction in some individuals, nests in human-inhabited areas may present an unacceptable hazard.

Most wasps are beneficial in their natural habitat, and are critically important in natural biocontrol. Paper wasps feed on nectar, and other insects, including caterpillars, flies and beetle larvae, and they are often considered to be beneficial by gardeners.