Impact of social wasps
German wasp.
German wasp
New Zealand has some of the highest densities of German and common wasps in the world. This is because they have no natural predators here, our winters are mild and there is plenty of food for them.
Social impacts
Wasps are a nuisance to forestry gangs, and a worry to tourist operators. They are unwelcome guests at summer picnics and barbecues. No-one finds a wasp sting a fun experience.
The venom from a wasp sting contains several toxins that can cause a hypersensitive or allergic reaction in some people.
Landcare Research (external site) provide detailed first aid advice.
Environmental impacts
Wasps are a major problem in some beech forests where they consume massive amounts of honeydew. Honeydew is produced by a native scale insect and is an important food for native birds, bats, insects and lizards.
Wasps also eat huge numbers of native insects and have even been seen killing newly hatched birds. By eating so much, they upset the natural food chain of the forest.
In some beech forests there are an estimated 12 nests, or 10,000 worker wasps, per hectare. This makes the numbers of wasps in these areas higher than that of all native birds, stoats and rodents, put together.
Landcare Research (external site) provide further information on the impacts of these wasps.
An evaluation of the costs of pest wasps in New Zealand This study assessed the economic impact of German wasps and common wasps across industries, society and the natural environment in New Zealand.