Yellow Jacket (Wasps)
Yellow jacket is the common name in North America for predatory wasps of the genera Vespula and Dolichovespula. Members of these genera are known simply as “wasps” in other English-speaking countries. Most of these are black and yellow; some are black and white like the bald-faced hornet, Dolichovespula maculata. Others may have the abdomen background color red instead of black. They can be identified by their distinctive markings, their occurrence only in colonies, and a characteristic, rapid, side to side flight pattern prior to landing. All females are capable of stinging. Despite having drawn the loathing of humans, yellow jackets are in fact important predators of pest insects.
In 1975, the German yellowjacket (Vespula germanica) first appeared in Ohio, and has now become the dominant species over the Eastern yellowjacket. It is bold and aggressive, and if provoked, it can sting repeatedly and painfully. It will mark aggressors, and will pursue them if provoked. It is often confused with Polistes dominula, an invasive species in the United States, due to their very similar pattern. The German yellow jacket builds its nests in cavities — not necessarily underground — with the peak worker population in temperate areas between 1,000 and 3,000 individuals between May to August, each colony producing several thousand new reproductives after this point, through November. The eastern yellow jacket builds its nests underground, also with the peak worker population between 1,000 and 3,000 individuals similar to the German yellow jacket. 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 on the source of the wood fibers used. The nests contain multiple, horizontal tiers of combs within. Larvae hang down in combs.
In the southeastern United States, where southern yellow jacket (Vespula squamosa) nests may persist through the winter, colony sizes of this species may reach 100,000 adult wasps. The same kind of nest expansion has occurred in Hawaii with the invasive western yellow jacket, Vespula pensylvanica.