wasp

Introduction

wasp, name applied to many winged insects of the order Hymenoptera, which also includes ants and bees. Most wasps are carnivorous, feeding on insects, grubs, or spiders. They have biting mouthparts, and the females have stings with which they paralyze their prey. The sting can be used repeatedly. The thorax of a wasp is attached to the abdomen by a narrow stalk (hence the term “wasp-waisted”). Some wasps are solid black or dark blue, but most have red, orange, or yellow wings or markings. Stripes are common. The great majority of the 20,000 species are solitary, but one family (the Vespidae) includes both social forms (the paper wasps, hornets, and yellow jackets) and solitary forms (e.g., the potter wasps).

Classification

Wasps are classified in the phylum Arthropoda, class Insecta, order Hymenoptera.

Parasitic Wasps

Some wasps are parasitic. The cuckoo wasps (family Chrysididae), of worldwide distribution, are brilliantly colored wasps that lay their eggs in other wasps' nests. The ichneumon flies are wasps that lay their eggs in the larvae of other insects. The gall wasps (see gall) lay eggs in plant tissues. Wasps that prey on harmful insects have been introduced in various regions to control these pests.

Solitary Wasps

Among the solitary wasps, each species usually favors a particular type of prey. The female seals a single egg in a nest provided with paralyzed prey on which the developing larva feeds. In many species the nest is in a burrow or small hole dug by the female. The jug-shaped nests of the potter, or mason, wasps (Eumenes and other genera) of Europe and North America are made of mud and fastened to plants. Often seen under bridges and eaves are the nests of the organ pipe mud dauber (Trypoxylon politum), consisting of long, narrow, adjacent cells of mud. Other solitary wasps are the tarantula hawks (Pepsis and Hemipepsis species) and cicada killers (Sphecius) of the SW United States, which hunt prey much larger than themselves.

In social wasp colonies there are usually three castes: the egg-laying queens (one or more per colony), the workers, or sexually undeveloped females, and the drones, or males. Social wasps build nests of a coarse, papery material, prepared by masticating wood fiber. The eggs are deposited in the compartments, or cells, of the nest, where they develop into larvae and then pupae, emerging as adults. Adult social wasps feed chiefly on nectar and plant sap but feed the larvae with masticated animal food. In temperate regions a colony lasts a single season, the drones and workers dying in the fall. The mated queens take shelter during the winter and in spring lay eggs and start new colonies. In the tropics colonies continue indefinitely, dividing when they grow very large. The paper wasps (Polistes), of nearly worldwide distribution, usually hang their nests, consisting of a single comb (layer of cells), from eaves, branches, or other shelters. The true hornets (Vespa) of Eurasia and their close relatives the yellow jackets, hornets, and wasps of Vespula and Dolichovespula, found in the Northern Hemisphere, build a large, round nest of many combs, covered with a paper sheath. In some species, primarily in the genus Vespula, the nest is built underground.

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