Xena, the warrior princess, is in hiding. From above, the terranium looks empty: just an expanse of coarse sand and a food tray. "You can see she's been out, she makes a bit of a mess," says Hamish Mack, delving into the coarse substrate with a spatula, revealing the cavity beneath and Xena hunkered down, her abdomen pushed against the glass.

There is no escaping. Xena is deftly scooped into a bottle and passed to me. I should know what the creature we will be looking for looks like. "You are holding the rarest insect in the world, or one of the rarest anyway," announces Liz Grant, her voice holding an odd mix of affection for the creature in the bottle, and an expectation of rebuff.
For Xena is not conventionally pretty. Xena, the giant tusked weta, is more the sort of creature small boys would use to tease their sisters with: an amber-coloured, panzered cricket, a palm's width in size.

"Look, you can see the tympanum," says Hamish, pointing at the joints of the forelegs, where Xena has the insect equivalent of ears.

Close up, Xena does seem a miracle of manufacture: the spikes on her legs, that long ovipositor, the gloss to her cuticle. "She's beautiful," I say. And she is - besides, it is not a bad line to take in front of Hamish and Liz, Xena's caregivers here in Massey's entomology lab.

Xena is a very rare creature, a long way from her island home. In a few days senior ecology lecturer Ian Stringer, who has been contracted by the Department of Conservation, fellow volunteer Halema Flanagan and I will be on Middle Island, off the coast of the Coromandel, spending our nights looking for others like her. Unsuccessfully.

But let's return to beginnings. Biologically speaking, New Zealand has an oddball fauna. When the scrap of land that would become New Zealand split and drifted away from the continent of Gondwanaland about 70 million years ago, mammals (except, perhaps, for bats) missed out on hitching a ride.

Evolution filled their ecological places with other creatures. Birds such as moas would become the ecological equivalent of browsing mammals, while giant wetas would become 'invertebrate mice'.

Later - much, much later - mountain building and glaciation would create isolated 'islands' of tolerable living conditions surrounded by seas of inhospitable terrain. Again, species would evolve to fit the conditions of their particular island.

Finally, as the glaciers receded and sea levels rose, more true islands would be created, yet again dividing and isolating populations (and later providing refuges for relict populations once the European and his pests arrived on the mainland). The result was a number of weta species.

Some had become very large - a common island phenomenon. The giant tusked weta is of a good size, but the weta contender for the title of heaviest insect in the world is Deinacrida heteracantha, which can be double the weight of a mouse. The species survives only on Little Barrier Island, where its tree-dwelling habits put it largely out of reach of the kiore (Polynesian rats) also living there.

The Mercury Islands, carrying the forebears of today's giant tusked weta population, were separated from the mainland about 8,500 years ago, though for periods the islands themselves may have been linked to one another.

Xena's ancestors co-evolved with a constant set of predators. For thousands of years the tusked weta successfully survived the attentions of tuataras, skinks and geckos, and a particularly nasty-looking giant centipede, none of which are averse to snacking on weta.

But put a nocturnal, ground-dwelling, mammalian hunter with a half-way decent sense of smell on the island and the weta's number is up. Stoats, ferrets, rats, mice: they all fit the bill.

Why mammals have never made it to Middle Island does not puzzle the visitor for long. Getting on to the island is often difficult (as well as being illegal without a permit). When the weather is good you get wet, when the sea is up there's no getting anywhere.

Ian Stringer made his first trip to Middle Island in late 1998. Since then he has had several 'swim-for-its' and once lost a stockpile of gear he thought he had out of harm's way. Every so often the sea mocks him with part of what it took. Among the driftwood, a set of diving goggles, less the lenses, or a tatter of neoprene. All calculated to annoy a man with a liking for order.

From the dinghy that takes you from launch to shore, barrels of gear and container after container of water are muscled up the red clay slopes to the shallow platforms on which the tents will be pitched.
Above in the canopy of mahoe and kawakawa parakeets (kakariki) chitter. In the distance the sea laps on the rocks. "The isle is full of noises, sounds and sweet airs, that give delight and hurt not," as that line of Shakespeare goes.

Night is another matter. Middle Island is warrened with seabird burrows. At round seven in the evening the owners - those who have not stayed behind to mind the eggs - begin to return, hitting the foliage and dropping to the ground like ripe fruit.

Diving petrels cry morn-iiiing, morn-iiiing, morn-iiiing in more and more hysterical tones as dawn and the return to sea draws near. Little shearwaters let loose with a manic ah-ha-ha-ah-ha-ha. Little blue penguins have a cry that is the stuff of bad horror movies.

The seabirds and their guano support a complex menagerie of creatures. Most are nocturnal. Come nightfall, every 100 metres or so there is another tuatara - first still as porcelain, then loping off, head angled high. There are geckos suspended in foliage, large skinks rustling through the leaf litter, and a host of invertebrates with complicated scientific names, which are spoken of in shorthand.

"Two round shiny beetles," dictates Ian, quartering the bush with his headlamp, "one little shearwater, oh, and one tute." This last said as a glimpse is caught of a tuatara tail flicking into a burrow.

This is the twice-nightly island routine: a slow-mo, headlamp-lit traverse of tracks which run round the plateau at either end of the Island. The data about what is spotted is later collated with weather, temperature and humidity readings.

Volunteer Halema Flannagan, an expert in skinks and geckos, is able to spot both with preternatural skill. But, really, the business of spotting beetles and geckos is more a way of maintaining concentration than anything else. We want tusked weta.In six nights of searching we do not find any. Instead we find the island's resident morepork, a sleeping wood pigeon, ground weta aplenty, and, glittering in the torchlight, a shard of volcanic glass, left behind by pre-European Maori.

Here are some good excuses for not finding giant tusked wetas. First, not that much of the island is suitable for them. Of Middle Island's 13 hectares less than half a hectare is good weta habitat. Second, there aren't that many tusked weta. Drawing on the results of a 14-day survey session, entomologist Mary McIntyre of Victoria University (who undertook most of the early work on giant tusked wetas) estimated a pool of about 120 active mid-sized juveniles and adults in the early '90s. Third, much of a weta's time is spent in its burrow, the entrance to which is plugged with a mix of soil and saliva. This particularly goes for those times when it is most likely to be spotted by predators. McIntyre records that one male remained underground for eight days, perhaps avoiding the full moon. Finally, even if they are out, the wetas are known to be cryptic: difficult to spot.

Despite managing on Middle Island for 8,500 years without the intervention of biologists, the giant tusked weta's continuing existence there is precarious. One major fire, one significant storm, or, in recent times, that castaway rat and it would be all over. Even now the hot, dry conditions of El Nino may be eating into what little suitable weta habitat there is.

"We have to assume that they are there in verylow numbers and very vulnerable,” says the Department of Conservation’s Chris Smuts-Kennedy, who is supervising the giant tusked weta project. So in the 90s DOC brought in LandCare to run a captive breeding and translocation programme and Massey to research the species. New populations of giant tusked weta are now established on Middle Island’s near neighbours, Red Mercury and Double Islands.

A female weta can lay a batch of between 100 and 200 eggs, but at first the breeding programme faltered. Unlike the other giant wetas, the tusked weta is carnivorous. “The males kill the females — you can only have them together for short periods,” says Chris, explaining the niceties of weta breeding. “You have to watch them till they’ve done the deed and then whip them apart again. And then the babies eat each other...” Now, he says, Chris Winks of LandCare has the care and breeding of giant tusked wetas down to a fine art.

This is one of conservation’s good news stories, says Chris Smuts-Kennedy, a programme that has assured the future of “the kakapo of the invertebrate world”.

If there is a flaw in the transplanted populations, it is that most of the wetas are the progeny of one father: Samson, a weta who was captured late in life, did his bit for the good of the species, and has since died. Having a population entirely descended from a single male is genetically risky — which explains Ian’s eagerness to find another. If one is found it will be whisked away to stud.

Why go to so much effort for a weta? Why indeed go to so much effort for any invertebrate? In the world of conservation, invertebrates are very much second-class citizens, says Ian Stringer. In New Zealand’s wildlife legislation, vertebrates — including introduced species — are given protection by default; invertebrate species must be singled out.

One reason for this may simply be that there are a hell of a lot of insect species. Then again our species has a penchant for animals who are like us — the so-called charismatic megafauna. Naturalist Konrad Lorenz has suggested that certain features of human babies — the large head, the big eyes — trigger our maternal and paternal instincts, our need to care for and protect.

Writer Tim Cahill describes animals like this as ‘fubsy’. Think of the koala bear, or the panda, symbol of the World Wildlife Foundation. Fubsy, aren’t they? In New Zealand most of our affection — and our research funding — is reserved for birds.
In Mäori legend, wetapunga was the god of ugly creatures. (The tusked weta’s scientific moniker, Motuweta isolata, translates as isolated island weta.) Most people look at a weta and reflexively pull back. Fubsyness rating: poor.

The popular perception is changing. The weta is becoming, if not New Zealand wildlife’s romantic lead, then a treasured character actor. Mary McIntyre often talks to school children and other interested groups about giant wetas. The similar-sized but more placid Cook Strait giant weta from Mana Island is happy enough to sit on the hand of some brave-in-front-of-the-classmates kid. Giant wetas, the children learn, are large, docile and unique to New Zealand. “Initially the kids would say ‘Yuck!’, then they’d start to say ‘Well I’ve never seen anything like that before,’” says McIntyre.

“They are now a flagship for all the forgotten world,” she observes. “The Department of Conservation has a lot of species that are hard to sell publicly. You need to have icon species to make people take notice, when the real concerns are the habitat loss and the predators.”

There is still much to be learned about the giant tusked weta. How old do they grow? In the laboratory they have been kept from hatchling to the eighth moult, and Stringer believes they will live for a couple more. The tusks after which the species takes its name appear only on older males and are apparently used in jousting matches to do with mating rights. But no one knows precisely how the tusks are employed in these matches.

Do the wetas “sing” to one another? Certainly the species has “ears” — a tympanum situated just above the elbow of each foreleg, a position giving the best achievable stereo sound reception. It has a voice: there are stridulatory pegs on the weta’s tusks, which it employs in the same way you might run a fingernail across the teeth of a comb. In larger males the pegs are often worn flat. A shrill alarm call has been heard and jousting males are also know to hiss at one another. But are there songs of courtship? No one knows. “We’ve only had one adult [male], and he was sort of geriatric,” said Ian Stringer with an indulgent chuckle.

Not a lot is left of primaeval New Zealand. Out- side the lab at Massey, where the research programme is taking place, the green grass of the Manawatu stretches out forever. The distant ranges are covered in bush, but bush empty of much of the life that would have been there a century ago. Places like Middle Island — and creatures like the giant tusked weta — are our connection with this older place.

On Middle Island you wash in salt water, snatch sleep when you can, and put up with the vagaries of sea and weather. But it’s all worth it to stand at night on the bouldery seaward shore and look across the other islands, their shapes blocked out against a sky crammed impossibly full of stars. Behind you the birds are making an unholy din, as they have every night for thousands of years. Somewhere, faith insists, tusked wetas are going about whatever it is that tusked wetas have gone about doing since the end of the last ice age.

From back in my civilised workaday life, I like to hold tight to the thought that it will continue that way every night of my lifetime and beyond.

Mary McIntyre

In May 1968, Mary McIntyre was in the first cohort of 13 students to graduate with BScs completed entirely at Massey University. There were, she says, few women on the main campus at the time "and plenty of parking space for the very few students with cars!"

After Massey, Mary went on to teacher training at the Christchurch College of Education, an MSc in Zoology at Canterbury, and then a doctorate as a junior lecturer at Victoria.

Currently she coordinates the Master of Conservation Science degree at Victoria, and is also involved with various conservation and environmental projects, both with students and her own account.
"The interest in wetas draws on a fascination with animal behaviour, first developed at Massey, and extended to insects in graduate studies.

The opportunity to become involved in weta conservation has been a challenging and fascinating way to apply scientific skills. It has also brought the chance to work on the offshore islands, which are the only places places where the largest giant weta now survive."