There are many species of solitary wasp in New Zealand. Most species use or burrow tunnels in the ground, hollow plant stems or holes in trees.
The mason wasp builds its nests out of earth and will often pack crevices between curtains and keyholes with its mud nests. Solitary wasps sting and paralyse insects or spiders, which they then drag back to their holes. One or two insects are stored in each hole and an egg is laid on top. The paralysed insect provides food for the wasp grub when it hatches.
A large Australian wasp found in Northland preys on cicadas. Other species known as "policeman" wasps prey on flies, spittlebugs, and cockroaches.
Golden hunters are conspicuous solitary wasps, with gold markings. Golden hunters, and a closely related species, the steel-blue spider hunter, are sometimes seen dragging paralysed spiders (which are often more than twice their size) into holes.
Parasitic ichneumon wasps often have long sword-like ovipositors and very thin "waists". They lay their eggs in caterpillars and beetle larvae which will be the food for the developing wasp. Ichneumon wasps are commonly used as biocontrol agents. NB: There are more than 100 species of ichneumon wasps in New Zealand.
One species of ichneumon wasp that hunts caterpillars at night and is often attracted to house lights is the "red soldier", which is also known as the "bloodsucker" — although it does not suck blood. The native giant ichneumonid can be up to 100mm long and parasitises the large wood-boring elephant weevil. The sirex wood wasp can be up to 40mm long, and is commonly found around pine plantations. It bores into tree trunks to lay its eggs, and because the larvae damage the wood it is considered a timber pest.
To control the sirex wood wasp another giant species of ichneumon wasp — Megarhyssa nortoni, which parasitises sirex wood wasps larvae — was introduced to New Zealand. This ichneumon is similar in size and appearance to the native giant and has an ovipositor that is twice as long as the body.
Another vespoid wasp from Europe is now firmly established in New Zealand — but this one may bring some benefits, especially for gardeners. However, they do sting, but only if you have soft young skin. Those of you with tough, leathery skin should be safe.Ancistrocerus gazella (Hymenoptera: Eumenidae) were first recorded in NewZealand just ten years ago, but are already widely distributed in both the North and South Islands.
Although the yellow and black colouration may make them look superficially like common or German wasps, they are immediately distinguishable by the quite different pattern of colouration and by the smaller size.
The females range in length from 11- 15mm, and the males from 7- 9mm.