One of the things that makes New Zealand’s ecosystem so unique is that, apart from three species of bat (one of which is now extinct), there were no land mammals present, until the arrival of humans. This meant that in the evolution of New Zealand’s native animals there were ecological niches that would have otherwise been taken up by mammals.

The weta take up an ecological niche that are similar to that of mice and rats. They are nocturnal and most are omnivorous, eating vegetation and other small invertebrates. Weta can pass seeds through their digestive tracts unharmed, and so are effective seed dispersers, similar to mice.

Male Tusked Weta (Photo: wikimedia commons)

There are around 70 species of weta, of which 16 species are endangered. They can be grouped into five main groups: tree weta, cave weta, ground weta, giant weta and tusked weta. The giant weta are very large for insects, weighing on average 20-30g. The heaviest on record is 70g. This was a captive weta whose abdomen was full of eggs at the time.  Female weta can easily be distinguished from male weta, as the females have what looks like a huge stinger, this is actually an ovipositor. It’s what she uses to lay her eggs. The ovipositor can be pushed deep into hard to get places, like into rotten wood, where the eggs will be safe until they hatch.

Female Giant Weta (Photo: Mike Locke)

Weta have received a fair amount of attention over the years. Many people find this weird insect fascinating. The highly successful Weta Studios is named after the insect because they are “a very cool, prickly little monster, unique to New Zealand.”  The weta has also featured in the popular TV series Man vs Wild. While in the North Island Bear Grylls ate a tree weta (a non-endangered species). He screwed up his face and spat some of it out stating it was rancid, and he has eaten some really disgusting things throughout the series!  However this does not deter the tuatara, kiwi or New Zealand’s only owl, the morepork, for whom weta are a common part of their diet.

Even though weta had predators before the arrival of humans to New Zealand, the introduction of mammalian predators to New Zealand has caused a dramatic decrease in weta numbers. Weta can be found in a wide variety of habitats, including grasslands, shrub lands, forests and caves. Weta prefer dark places, and are usually found hiding under rotting logs, in crevices in trees or other similar places. As their name suggests cave weta can be found in caves, but they are also commonly found in the bush.

Female Cave Weta (Photo: Erin Bowkett)