yellow jacket

yellow jacket, any of 35–40 species (genera Dolichovespula and Vespula) of social wasps, principally of the Northern Hemisphere. Despite the common name yellow jacket—which is used in reference to the typical coloration of the abdomen, with yellow and black markings—some species are white and black, and others are marked with red. Like hornets, yellow jackets differ from other wasps in having their wings folded longitudinally when at rest.

(Read Britannica’s essay “What’s the Difference Between Hornets and Wasps?”)

Natural history and life cycle

As social wasps, yellow jacket societies have a caste system consisting of one or several queens, a few drones (males), and sterile females called workers. The queen, a fertilized female, begins the colony in the spring by building a small nest and laying eggs that hatch into workers. The latter enlarge the paperlike nest, which is composed of chewed dry plant material, usually wood, that has been mixed with saliva and regurgitated. The nest consists of one or more layers of cells that are arranged vertically with the openings downward. Depending on the species, the nest may be found in cavities in the soil, in tree trunks, or hanging from leaves, branches, or the eaves of buildings. Dolichovespula species typically build exposed nests. Vespula species build concealed nests underground or in protected cavities; when a nest is stepped on, the colony may erupt in an angry, stinging swarm. Nest size varies widely; some nests can be held in one hand, whereas nests in warmer climates may weigh half a ton.

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Paper wasp

Hornet

Northern giant hornet

Cuckoo wasp