german wasp that colonised NZ beech forest in vast numbers

Size
Length: 1–1.5 cm
Lifespan
1–2 years
Diet
Larvae feed on protein-rich insect matter pre-chewed by workers. Adults feed on nectar, honeydew and fruit. Workers hunt insects, spiders and carrion to feed colony's larvae.
Habitat
Everywhere: forests, gardens, urban areas and rural farmland. The aggressive invaders, building massive nests in ground, wall cavities and tree hollows. In beech forests, reach extraordinary densities.
Range
Throughout North and South Islands in forests, gardens, urban areas and rural farmland. Most common in beech forests of South Island where honeydew provides abundant food for large colonies.
Endemism
Invasive
Main Threats
None. This introduced pest is widespread and abundant. Controlled using targeted poison baits and nest destruction, particularly in beech forests where wasp densities reach world-record levels.
Population
Arrived in 1940s and has become one of New Zealand's most destructive pests. Densities in some beech forests are higher than anywhere else in the world. Devastate native invertebrate populations.
Conservation Status
Introduced
A few years ago I accidentally disturbed a nest and was stung at least six times in the space of a few seconds. No vodka was strong enough to negotiate with the pain. Being German-born, I also lost what little faith I had left in something resembling comradeship. The German wasp is the bully of the New Zealand bush. Yellow, black and bristling with aggression, it arrives in spring to build paper nests that can grow to the size of a car tyre, housing tens of thousands of workers. Unlike the native fauna, which evolved without such intense competition, the German wasp operates with ruthless efficiency. They hunt native caterpillars, spiders and beetles, stripping the forest floor of life to feed their voracious larvae. A wasp that is a bully. Their most devastating impact is in the South Island beech forests. Here, they compete directly with native birds like the kākā and tūī for honeydew, a sugary exudate from scale insects on beech trees. A single wasp nest can consume kilograms of honeydew per day, starving the native birds and disrupting the entire food web. They are active from early spring until the first hard frost, meaning they dominate the ecosystem for most of the year. For humans, they are a nuisance and a danger. Their nests are often hidden in inconspicuous places, leading to accidental stings. They are attracted to sweet drinks and meat, making summer picnics a minefield. Control efforts involving aerial baiting are conducted annually, but the sheer number of queens that survive winter makes eradication impossible. They are a stark reminder of the fragility of island ecosystems when faced with a highly adaptable, aggressive invader. The beech forest is quiet. The wasp nest hangs from a branch, papery and grey, tens of thousands of workers inside. They hunt. They strip the forest floor. They take the honeydew. The kākā go hungry. The wasps do not care. They do not know they are invaders. They do not know they are bullies. They just want to feed their larvae. The unintended consequences of global movement and the high cost of biosecurity failures. The German wasp is proof.