The median wasp, Dolichovespula media, is a wasp

Wasp

The term wasp is typically defined as any insect of the order Hymenoptera and suborder Apocrita that is neither a bee nor an ant. Almost every pest insect species has at least one wasp species that preys upon it or parasitizes it, making wasps critically important in natural control of their...

 of the genus Dolichovespula

Dolichovespula

Dolichovespula is a small genus of social wasps distributed widely throughout the Northern Hemisphere. The yellow and black members of the genus are known by the common name yellowjackets in North America along with members of their sister genus Vespula...

native to Europe. Aside from its black-and-yellow coloration, it is very similar to Dolichovespula maculata, the bald-faced hornet

Bald-faced hornet

Dolichovespula maculata is a North American insect commonly called the bald-faced hornet...

, which is found in the USA, Alaska

Alaska

Alaska is the largest state in the United States by area. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...

 and Canada

Canada

Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

.
The highly active workers need mainly only carbohydrates. So adults collect nectar from flowers. For the queen and to feed their young larva

Larva

A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...

e, they hunt many kind of insects — like flies and other wasps.

Their nests usually hang from tree or bush branches, and they can be aggressive in defence of them.

Although their nest's life cycle is short, future queens ("gyne

Gyne

Gyne is the primary reproductive female caste of social insects . Gynes are those destined to become queens, whereas female workers are typically sterile and cannot become queens...

s") can survive through the winter, and the result is multiple egglaying queens that abandon the mother nest in search for a new nest.