Facts, Identification & Control
Vespula spp. and Dolichovespula spp.
Yellow jackets, genera Dolichovespula and Vespula, get their name from their yellow and black bodies. They measure 10 to 16 mm in length. Most yellow jackets are black and yellow, although some may exhibit white and black coloration. In contrast to the bee, the yellow jacket’s waist is thinner and defined. Their elongated wings are as long as the body and fold laterally when at rest.
Yellow jackets are wasps that can be identified by their alternating black and yellow body segments and small size. They are often mistaken for bees, although their bodies lack the same amount of hair, rounded abdomen, and the expanded hind leg used for carrying pollen of the bee. These social wasps live in colonies that may contain thousands of insects at a time.
Behavior, Diet & Habits
Yellow jackets are pollinators and may also be considered beneficial because they eat beetle grubs, flies and other harmful pests. However, they are also known scavengers who eat meat, fish and sugary substances, making them a nuisance near trash receptacles and picnics.
Many yellow jackets are ground-nesters. Their colonies can be found under porches or steps, in sidewalk cracks, around railroad ties or at the base of trees. Sometimes the queen uses a wall void of a building as a nesting place. Some yellow jackets build aerial nests in bushes or low-hanging branches or in the corners of buildings and other manmade structures.
A queen yellow jacket starts a new nest by building a small paper nest in which she lays the first batch of eggs. After hatching, these eggs are fed by the queen until they are ready to pupate and mature into adult yellow jackets. Adults live through one season and feed on caterpillars, grubs and other insects. They also enjoy nectar and sweet substances such as fruit and tree sap. Yellow jackets are attracted to garbage and other human foods, particularly meats and sweets.
A colony may contain 1,000 or more workers by fall. All of the workers are sterile females. In late summer males will begin to appear. When they become adults, they will mate with the females that will become the next year’s queens. The fertilized females will hibernate through the winter. The workers and the males will perish when the weather turns cold.
Signs of a Yellow Jacket Infestation
Yellow jackets usually are detected when workers are encountered. Nests, particularly the aerial nests, also may be a sign.
Yellow Jacket Stings
Known to be aggressive defenders of their colonies, yellow jackets are otherwise not quick to sting. The sting of a yellow jacket is painful, and each insect is capable of delivering multiple stings. Because they are equipped with lancelike stingers with small barbs, compared to the larger barbs in honey bees, yellow jackets are capable of stinging repeatedly. Yellow jacket stings may induce severe allergic reactions in some individuals.