Overview
In their isolated island setting, with few competitors or predators, giant wētā 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 wētā – 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 wētā 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 wētā lives on rocky slopes high above the range of these small mammals. The Mahoenui giant wētā 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 wētāpunga 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 wētāpunga. 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 wētāpunga, and its numbers are still diminishing.
Scientists are studying endangered species of wētā 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 wētā in their haunts. They are collecting eggs, hatching them, and raising young wētā 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.
Text originally published in Tai Awatea, Te Papa's onfloor multimedia database.