WETA WETAWetas are fairly common and
wander into New Zealand people's houses.
If they don't wander in by accident, the family cat will oblige.
This causes some consternation to the ladies of the household , who generally request the gentlemen to: "Remove that horrible thing now."
[Female
in 3D] [Male] [Big heads] [Black
Heads] [Predators]
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Wetas are more often seen at night - or they are if you carry a torch around the garden and look for them. Wetas like living in the wood pile, because normally they live in holes excavated in trees. They are omnivorous, but prefer other insects to fruit. In captivity they like carrot. The common tree weta is not a great hunter, but there are many weta species and the rarely seen ground wetas jump onto other insects. Ladies should fear not - the common tree weta does not want to enter houses and does not jump on people, in fact he has no interest in attacking ladies at all. Any insect he catches is usually dead or sick, so avoid panic if you see a big weta, you are not his prey.
Female Auckland Tree Weta.
Hemideina thoracica
This image is in X stereo format. Click for multi-format version
Female wetas have a long spine at the back for laying eggs (ovipositor). Frightened people think the ovipositor is a sting, but it is not.
Boy wetas have those two curved bits out the back, called cerci. Girls have cerci too: it seems they act as vibration detectors.
[Female
in 3D] [Male] [Big heads] [Black
Heads] [Predators]
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Here we see a weta climbing to the top of a log at sunset, ready to forage for - most things. Wetas took the place of rodents in early New Zealand, when there were no mammals.
A male Auckland Tree Weta.
√ Tree weta antennae are separated, instead of nearly touching at the base.
√ Tree weta feet have white pads behind the claw. (Antennae and feet distinguish Tree Wetas from over 50 species of Cave Wetas).
X No ovipositor (long black spike, like a tail), so he is not a female.
√ His back legs have a few big sharp spines (true for tree and giant wetas, but tusk and ground wetas have lots of little spines on their back tibiae).
X He does not have a tusk on his head.
√ He has two cerci at the back (two white curved "horns"), which is true for all wetas, male and female.
√ His black head is the same width as his thorax. (Giant wetas have a thorax wider than the head).
√ His face is very black (Wellington tree wetas have brown faces).
Ears are on the front legs, but there are two other ear-like organs. The paired cerci at the back are vibration detectors. Wetas often sit face into tree holes, with the cerci checking the environment. The back legs are folded protectively and small animals entering the hole meet with sharp spines.
Male wetas have big heads, but head size is very variable even in the same species, which is another peculiar thing about these ancient New Zealand insects. Big headed males fight better, because their mandibles are larger. But big heads do not get more girl wetas. While the big heads are making war, the little heads are wandering about making love. Maybe there is a moral here for big headed humans?
The big black head is a feature of Auckland tree wetas. Wellington tree wetas have brown heads. However, some Auckland females have a brown rim to their black heads, as shown here.
Head of a female Auckland Tree Weta
Click here to see this image in stereo.
Ears are easily seen in the pictures as the pale oval with a central black spot on the front tibias.
Feet have soft pads to help on slippery surfaces (the white pearl-like pads bottom right).
There are two compound eyes (black protruding ovals) plus a little eye between them (the orange spot between the antennae, called an ocellus). When you shine a torch on a weta at night, the ocellus may reflect back at you, like cat's eyes.
Mouth-pieces
The hard biting jaws are operated by strong muscles, which take up most of the space inside the head.
Palps are the two small jointed levers attached to the accessory jaws (there is another pair of palps on the far side). These palps taste the food, like our tongue and nose.
The bigger front palp comes from the maxilla while the smaller rear palp is attached to the lower lip.
The big main jaws in front (the mandibles) do not have any palps. In front of the powerful black mandibles there is an upper lip or labrum (white).
[Female
in 3D] [Male] [Big heads] [Black
Heads] [Predators]
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Wetas are so big, they make delicious food for Tuataras:
Kiwis and wekas (flightless ground birds) eat them too.
Moreporks (New Zealand Owls) have night vision and find wetas at night, sitting on tree trunks.
Kaka (New Zealand Parrots) can get them in daylight, by excavating the tree hole that wetas live in.
Saddlebacks reach into the holes to catch weta.
Apart from the owl, these ancient predators are now rare.Rats and other small mammals introduced by man are more recent predators.
The biggest wetas in the world are found in New Zealand: the Giant Wetas (Deinacrida sp.) (Deinacrida means "Demon Grasshopper") (Wetapunga in Maori). Tree wetas illustrated here are Hemideinacrida, hinting they are only half demons.
Other Gondwanaland (southern) continents have smaller weta species and a few "king crickets" have wandered into North America from South America.
[Female
in 3D] [Male] [Big heads] [Black
Heads] [Predators]
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to: Animals
Digital photography by John Wattie
(Nikon CoolPix 950 for the male, 4500 for the female.
