The nests consist of numerous hexagonal cells inside a thick paper covering. Most yellow jackets nest underground, but sometimes nests can be found hanging in trees or bushes, or within hollows in old stumps or the walls of buildings. Queen yellow jacket Yellow jackets eat primarily to feed their young. Most species prey on living insects. They consume large numbers of flies, caterpillars, and other pests.
Some species feed chiefly on dead animal matter, such as decaying fish and processed sandwich meats.
Yellow jackets also feed on sweet, sugary substances, such as ripe fruit and soft drinks. Such feeding habits often make yellow jackets a nuisance at picnics and campsites. Males and queens do not sting, but workers will vigorously defend a nest if it is disturbed, often stinging repeatedly. People are sometimes stung when they run lawn mowers over hidden nests. If stung, they may require immediate medical attention.