The nest is made from chewed plant fibres, mixed with saliva. It is generally found close to or in the ground, rather than higher up on bushes and trees like hornets. It has open cells and a petiole attaching the nest to the substrate. The wasps produce a chemical which repels ants, and secrete it around the base of this petiole to avoid ant predation. A solitary female queen starts the nest, building 20–30 cells before initial egg-laying. This phase begins in spring, depending on climatic conditions. She fashions a petiole and produces a single cell at the end of it. Six further cells are then added around this to produce the characteristic hexagonal shape of the nest cells.
Once the larvae have hatched as workers, they take up most of the colony’s foraging, brood care and nest maintenance. A finished nest may be 20–30 cm across and contain 3,000 individuals.Each wasp colony includes one queen and a number of sterile workers. Colonies usually last only one year, all but the queen dying at the onset of winter. However, in mild climates such as New Zealand, around 10% of the colonies survive the winter. New queens and males (drones) are produced towards the end of the summer, and after mating, the queen overwinters in a crack or other sheltered location. This common and widespread wasp collects insects, including caterpillars, to feed to its larvae, and is therefore generally beneficial. The adults feed on nectar and sweet fruit, and are also attracted to human food and food waste, particularly sodas and meats.