In their isolated island setting, with few competitors or predators, giant weta survived and thrived here for 80 million years, some even becoming truly gigantic. Since people and their animal baggage have arrived, most of these species have been in retreat. Today all but one – the scree weta – are endangered, and are protected by law. They cannot be collected, handled, or studied alive without special permits from the Department of Conservation.
Few giant weta remain on the mainland. Cats, rats, stoats, ferrets, and weasels have taken the biggest toll on them. Today’s populations are surviving only in places where they can be protected from these predators. For example, the scree weta lives on rocky slopes high above the range of these small mammals. The Mahoenui giant weta has adapted to making the spiny foliage of gorse its home - an inhospitable place for its enemies. It’s found in just one small patch of dense ‘old man’ gorse. This island on land was made a reserve when the species was discovered. Several other species survive only on predator-free islands offshore.
The wetapunga has to share Little Barrier Island with the kiore, the Polynesian rat. Conservation officers got rid of the cat population there. This benefited many of the birds and lizards on the island, but it had a surprisingly bad effect on wetapunga. The kiore was the cats’ main prey. Since the cats have gone, the kiore population has grown. Kiore are now putting even more pressure on wetapunga, and its numbers are still diminishing.
Scientists are studying endangered species of weta to gather information on their ways of life, so they can establish new populations in safe places. They are using miniature tracking equipment, such as tags, tiny transmitters, and lights fastened to the insects’ thorax, to help track weta in their haunts. They are collecting eggs, hatching them, and raising young weta in captivity, preparing them for release back into the wild.
In this way, we can hope to preserve the tiny remnant of these ancient forms of life.
Weta with a radio transmitter on its thorax Mana Island Photographed by Mary McIntyre Courtesy of Mary McIntyre