and pollen. Newly emerged bees do not have food stored in their nest, but they are occasionally brought nectar. X. virginica use their maxillae to penetrate the corolla of plants and reach the nectar stores, a behavior known as nectar robbing. This happens when the bee pierces the corollas of long-tubed flowers, thus accessing nectar without making contact with the anthers and bypassing pollination. In some plants this reduces fruit production and seed number. In other plants, defensive mechanisms allow pollination to occur despite perforation of the corolla. Mating behavior Each nest usually has one mated individual. Mating occurs in April and is often accompanied by a bobbing dance that involves about a dozen males and only a few females. Males require female activity, specifically flight, in mating. Occasionally before mating, the couple will face each other and hover for a few minutes. When the male contacts the female, he mounts her back and attempts to push his abdomen under hers. Copulation then occurs, and it is almost always followed by more mating attempts. If, during copulation, the female lands, the couple will disengage and the male will hover waiting for the female to take flight again; however, although the males almost always disengage and pause copulation when the female lands, there have been instances recorded in which the males will hold on to the female with all six legs and flap his wings in an attempt to lift her back into the air. Larger males are usually more successful in mating. Because of their competitive advantage due to their size, males will likely claim a territory near female nest sites. Smaller males will stay at foraging sites or other areas they think females may pass so they can mate with reduced competition. Kin selection Research has shown that, regardless of sex, X. virginica show more aggression toward non-nestmates than nestmates, indicating that they can recognize each other. By living in social groups with inclusive fitness, the bees can raise offspring with the help of the nest community rather than as a solitary effort. The ability of X. virginica to recognize nestmates allows primaries and secondaries to exclude tertiary bees from their nests. Tertiary bees are a burden on resources because they do not perform any useful activities, but they benefit from the food and shelter provided by the primary females. Defense Territorial behavior in males Males will establish territories