form of trophallaxis. As insect sources of food diminish in late summer, larvae produce less for workers to eat. Foraging workers pursue sources of sugar outside the nest including ripe fruits and human garbage. Notable species European yellowjackets, the German wasp (Vespula germanica), and the common wasp (Vespula vulgaris) were originally native to Europe, but are now established in southern Africa, New Zealand, and eastern Australia The North American yellowjacket (Vespula alascensis), eastern yellowjacket (Vespula maculifrons), western yellowjacket (Vespula pensylvanica), and prairie yellowjacket (Vespula atropilosa) are native to North America. Southern yellowjacket (Vespula squamosa) Bald-faced hornets (Dolichovespula maculata) belong among the yellowjackets rather than the true hornets. They are not usually called "yellowjackets" because of their ivory-on-black coloration. Aerial yellowjacket (Dolichovespula arenaria) Tree wasp (Dolichovespula sylvestris) Nest Dolichovespula species such as the aerial yellowjacket, D. arenaria, and the bald-faced hornet, tend to create exposed aerial nests. This feature is shared with some true hornets, which has led to some naming confusion. Vespula species, in contrast, build concealed nests, usually underground. Yellowjacket nests usually last for only one season, dying off in winter. The nest is started by a single queen, called the "foundress". Typically, a nest can reach the size of a basketball by the end of a season. In parts of Australia, New Zealand, the Pacific Islands, and southern coastal areas of the United States, the winters are mild enough to allow nest overwintering. Nests that survive multiple seasons become massive and often possess multiple egg-laying queens. In the United States The German yellowjacket (V. germanica) first appeared in Ohio in 1975, and has now become the dominant species over the eastern yellowjacket. It is bold and aggressive and can sting repeatedly and painfully. It will mark aggressors and pursue them. It is often confused with Polistes dominula, an invasive species in the United States, due to their very similar pattern. The German yellowjacket builds its nests in cavities—not necessarily underground—with the peak worker population in temperate areas between 1000 and 3000 individuals between May and August. Each colony produces several thousand new reproductives after this point through November. The eastern yellowjacket builds its nests underground, also with the peak worker population between 1000 and 3000 individuals, similar to the German yellowjacket. Nests are built entirely of wood fiber and are completely enclosed except for a small entrance at the bottom. The color of the paper is highly dependent