The median wasp (Dolichovespula media) is a species of social wasp of the family Vespidae found throughout Europe and Asia. It builds aerial paper nests often in shrubs or trees, and occasionally under the eaves of buildings. It is most common to see this wasp between May and October during its 3.3 month colony cycle. Behaviours of this wasp include nest defense, curling which is believed to function in brood incubation, and gastral vibration which is involved in larval feeding. Most foraging in the nest is done by the workers once the first ones reach adulthood. These workers forage for insects, nectar, and wood for nest construction in temperatures as low as . This wasp is part of the subfamily Vespinae which includes all hornets and yellowjackets. It has also been sighted in New Zealand, but it is not known if the wasp is widespread in the area or if this was an isolated occurrence.
D. media builds aerial paper nests above ground. These nests are typically found in shrubs, trees, and sometimes under the eaves of buildings. Colonies are often found in both urban and rural areas. These wasps prefer to build nests close to the ground where humidity levels are higher as well as in open areas where the nest is subject to large amounts of sunlight.
Colony cycle
The colony cycle of D. media is about 3.3 months and occurs between early May and the end of August. thumb|left|200px|Queen The queen rears about 10 workers by herself and it takes about 30 days for these workers to mature to adults from eggs. It may function in thermoregulation or defense. This species lives in cooler temperate climates and nests in the open so thermoregulation is a plausible explanation, but so far no other vestibule of this length have been observed in species that live in similar climates. It is not known if this fungus kills living wasps or if it simply attacks dead insects, but there is some evidence to suggest that overwintering queens can be infected. The sting of the median wasp is comparable to many other wasp species and should be treated with a cold compress and an antihistamine to reduce swelling unless a more serious allergic reaction occurs.