Vespula germanica, sometimes known as the European wasp, is native to temperate Asia, North Africa, and Europe. However, the European hornet has spread outside of its natural habitat to North America, New Zealand, South Africa, South America, and Australia. In 1959 these came to Tasmania. Since then, they has moved to Victoria, New South Wales, South Australia, and Western Australia. Isolated nests have also been discovered in southern Queensland.
Being a scavenger insect, the European wasp prefers to live with people to share our food and crops. It was first observed in Melbourne in 1977 and had colonized large areas of Melbourne within five years. By the 1990s, the European wasp had invaded most other areas of Victoria.
The European wasp is similar in size to the worker bee, about 15 mm long, but it is less hairy and has a visible lemon-yellow stripe along its black body. Males and queens are larger, measuring 17–20 mm long, although they still have the same patterns as the workers.
Although each nest usually lasts a year, the nest remains and grows in warmer regions. The males die in winter, and the newly mated queen hibernates in preparation for the spring nesting season. Each egg the queen lays in the nest cells hatches into a larva in about 6 to 8 days. The queen takes care of the larvae for several weeks.
The larva develops in several instars (instars). The larva must pass through five stages before wrapping itself in a cocoon. The total duration of the larval stage varies from 9 to 22 days, depending on temperature and food availability.
When fully fed, the larva uses the silk secreted by the salivary glands to weave a cocoon within its cell. It takes 7-9 days for the larva or pupa inside the cocoon to grow into an adult. They become the first group of workers responsible for building the nest and raising the larvae while the queen lays her eggs.
The large communal nests that house European wasps are usually only visible as small entrance holes. They are usually built underground or in cracks in logs, walls, or ceilings. Woodpecker nests can be found in the ground, logs, tree trunks, and wall and ceiling cavities.
The old nest eventually collapses in Europe, and the scattered queens hibernate in shaded areas under loose tree bark or in treetops. The legs, wings, and antennae of the hibernating queen are folded under her as she clings to the substrate with her teeth and remains immobile for up to six months.
It is remarkable that one of the new queens can stay in the nest and start laying eggs in the warmer climate of Australia without going through the usual hibernation period. This can produce huge and potentially dangerous wasp nests over several seasons.