Exciting news: I’m going on my honeymoon next week! My husband and I will spend a little over two weeks in New Zealand.
We’re planning on a few hikes to see local animals, like kiwis and albatrosses. But there’s one animal we might see whether we like it or not: the wētā.
Wētā are large insects endemic to New Zealand and are related to crickets, locusts, and grasshoppers. Over 100 species of wētā are on the islands, coming in various sizes. Wētā are generally recognizable by their large bodies, spiny legs, and curved tusks. These insects are mainly nocturnal herbivores, with some smaller species living as carnivores or scavengers.
Five wētā groups
There are five broad categories of wētā living in New Zealand:
Tree wētā
While there are only 7 species of tree wētā, they are the most common type of wētā found in New Zealand. You can find tree wētā living in tree holes created by other insects or rot. Once a hole is found, the tree wētā will keep the opening unobstructed by removing any surrounding bark. A single hole or wētā gallery can house a male and a harem of up to ten females.
Ground wētā
The approximately 30 species of ground wētā spend their day hiding in burrows in the ground. Some even cover their exit with a specially-made door! At night, ground wētā hunt invertebrates and fruit. Most female ground wētā have long ovipositors for laying eggs. Some species even provide maternal care to their eggs.
Cave wētā
Cave wētā are the largest group of wētā, with around 60 different species described. These species are only distantly related to the other types of wētā and are recognizable by their extra-long antennae. Cave wētā may also have long, slender legs, and some are sensitive to ground vibrations. Unlike other wētā, cave wētā don’t have hearing organs in their front legs. Their name is also a bit of a misnomer: while some cave wētā live in caves, many live in the forest.
Tusked wētā
Only three species of tusked wētā are currently known to scientists, all of whom are mainly carnivorous and eat worms and insects. While female tusked wētā look very similar to ground wētā, males have long, curved tusks pointing forward on their mandibles. These tusks are used for male-male combat.
Giant wētā
There are 11 species of giant wētā, most of which are found on small islands off the coast of New Zealand or in high elevations on the South Island. Giant wētā are generally less social than tree wētā.
Giant wētā
The largest of the giant wētā is the wētāpunga. Its name is Māori and means “god of ugly things.” You can only find wētāpunga today on Hauturu-o-Toi (the Little Barrier Island).
It’s hard to overstate just how big wētāpunga can get. Females grow heavier than adults and can weigh up to 35 grams. To put that in perspective, that’s within the average weight range of house sparrows and mice. The wētāpunga holds the world record for the world’s heaviest insect, with one female reaching 71 grams! While other wētā can jump to some degree, the wētāpunga’s large size keeps it earth-bound.
But while their size may freak you out, wētāpunga are generally harmless to humans; they’re usually slower and less aggressive than other wētā. Wētāpunga also can’t kick or bite, relying instead on making a hissing sound to deter predators. Wētāpunga spend their days hiding in dead foliage, coming out at night to feed and find mates.
Dinosaur times
Wētā have been on Earth for a long time: 190 million years! Today’s wētā are virtually unchanged from fossilized, prehistoric wētā.
Wētā benefited from evolving on an island. Islands are difficult for land mammals to reach, leading to some evolutionary weirdness. No wētā can fly, for example, since they never had to escape terrestrial mammal predators. A lack of mammals also opened up a niche for insects or birds to take over. In New Zealand, the wētāpunga specifically filled the role traditionally occupied by rodents like mice and rats.
Unfortunately, wētā breed much slower than rats and mice. When humans made it to New Zealand and brought along rodent hitchhikers, wētā, like the wētāpunga, struggled to compete for food. Rats and mice also found wētā larvae a tasty snack, further decreasing the population.
But there’s good news: conservation efforts have increased wētāpunga population levels. With further protection, we can keep this living fossil from becoming an actual fossil.
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