Workers feed the larvae with various insects that they have first chewed, and other sources of animal protein. They themselves feed on sweet substances. When they land on our food they are looking for either type of nutrient.
Wasps and hornets have stingers and use them to defend themselves or the colony. The venom they inject also paralyzes their prey, which they can then keep alive in their nests.
In our climate, social wasp nests are used only once, and workers build new ones every year. There are two kinds of paper nests. Those made by hornets in the Vespinae subfamily are covered in paper and have an opening at the base. They can be quite large. These nests consist of many rows of brood cells for developing larvae. They are often found attached to the walls of houses, but may also be hidden in trees.
Nests built by paper wasps in the Polistinae subfamily are open, so that the brood cells are visible. These nests are suspended from a small stalk and are smaller, with only a single row of cells, all opening downward.
The paper used to make the nests is a pulp consisting of plant fibre mixed with the wasps’ saliva. Its colour depends on what it is made of, i.e. wood fibre, bark, stems, cardboard, etc. The different species may have preferences in choosing the fibres they use.
It was by observing wasps, in 1720, that French naturalist Réaumur came up with the idea of using wood fibre to make paper. At the time, Europeans still made their paper from rags. Some one hundred years later, paper made from wood pulp appeared.