This prickly stick insect was found on a Dunedin rose bush this week. Photo by Alan Gilchrist.
Fairfield resident Alan Gilchrist had a close encounter with
an unusual and prickly visitor this week, and has asked
himself a few thorny questions.
Mr Gilchrist (75) noticed the longest and most
unusual-looking stick insect he had ever seen, on one of his
wife Jeanne's rose bushes.
The green stick insect's body was about 11cm long and
seemingly covered in dark prickles or thorns.
It looked quite different from the slightly shorter common
stick insect, which has a smoother body, although it can take
many forms and colours.
"I just thought: 'This is a bigger one than I've ever seen
before'," he said.
"It's unusual. I thought someone would be interested."
Accordingly, he took two digital photographs, which he
emailed to the Otago Daily Times. They were then sent
to Anthony Harris, an honorary curator of entomology at the
He quickly identified the creature as the prickly stick
insect, known formally as Acanthoxyla prasina.
This native insect is found throughout New Zealand, although
it is less frequently reported than the "common" stick insect
Mr Harris had last seen a prickly stick insect about two
years ago, and said this was a handsome specimen.
"It's always a joy to see one of our beautiful insects," he
Mr Gilchrist's two other thorny questions were: how such a
sizeable and slow-moving creature survived predators, and how
it managed to find a mate.
Mr Harris explained that highly effective camouflage was this
insect's best protection.
"They're very hard to find. They're very well disguised."
The thorns are apparently part of the camouflage, but
prospective mates seeking less prickly companionship need
have no fear.
This species is parthenogenetic, producing eggs without the
help of a male, and no male prickly stick insects have yet
Although native to New Zealand, the insect has also been
accidentally introduced into England, where it breeds well.
It eats leaves of a wide variety of plants, but does almost
no lasting damage, he notes.
• Argosarchus horridus, New Zealand's largest stick
insect, has a body up to 14.8cm long. With its legs spread
out, it can fill the interior of a shoe box.