Friday, November 16, 2012


The walking stick insects of Ball's Pyramid. 

Ball’s Pyramid is not a man-made pyramid, but the remains of a massive volcano that emerged from the sea about 7 million years ago. It juts 562 metres out of the Pacific Ocean, off the coast of Australia, near Lord Howe Island. Ball’s Pyramid is named after the British naval officer Lieutenant Henry Lidgbird Ball, who was the first European to see it in 1788. 

The island was thought devoid of life until a scientific expedition led by David Priddel and Nicholas Carlile in 2001 discovered fresh droppings of some large insect under a single melaleuca bush 30 metres up the rock face. The team went back to the site after dark and discovered a colony of 24 of the Lord Howe Island stick insect (Dryococelus australis); the species had not been seen alive for over 70 years. These insects are known as ‘land lobsters’ or ‘walking sausages’ and are 15 cm long; they are the heaviest flightless stick insects in the world. 

The insects were once common on Lord Howe Island, but were presumed driven into extinction by black rats, which were introduced to the island when a supply ship ran aground on its shores in 1918. Somehow some of these wingless insects had escaped Lord Howe Island and travelled 22.5 km over open ocean to land on Ball’s Pyramid; how this happened is still a mystery. 

Two years after their re-discovery, Australian officials allowed four of the species to be retrieved. One pair was given to a man who was very familiar with mainland walking stick insects; he was a private breeder living in Sydney. Unfortunately within two weeks, the pair had died. The other pair collected from the island was named ‘Adam’ and ‘Eve’ and were taken to the Melbourne Zoo and placed with Patrick Honan, of the zoo's invertebrate conservation breeding group (the image shows Patrick Honan holding two of the Lord Howe stick insects). Eve laid little pea-shaped eggs, but then became very sick. Honan developed a mixture that included calcium and nectar and fed it to Eve, drop by drop. She recovered within a few hours. Eve’s eggs were harvested and incubated, though only the first 30 were fertile. Her offspring became the zoo’s new population of walking sticks.

Jane Goodall visited the Melbourne Zoo in 2008 and Honan showed her the rows and rows of 11,376 incubating eggs. At the time, there were 700 adults in the adult population; Lord Howe Island walking sticks seem to pair off. Goodall reported that Honan showed her photos of how the walking sticks sleep at night: “…in pairs, the male with three of his legs protectively over the female beside him."

Before any of these walking stick insects can be released back onto Lord Howe Island, a massive rat annihilation programme would need to be mounted. As this annihilation project would be costly, and it’s possible not all those who live on Lord Howe Island would enjoy seeing these huge, hard-shell crawling insects back, the Melbourne Museum is considering a public relations campaign on behalf of the insect. 

This video features a new baby walking stick insect emerging from its egg: http://vimeo.com/14413689#

-TEL

Read about how Ball's Pyramid formed here: http://on.fb.me/T6pPMw

http://www.npr.org/blogs/krulwich/2012/02/24/147367644/six-legged-giant-finds-secret-hideaway-hides-for-80-years; http://atlasobscura.com/place/balls-pyramid
Image credit: Rod Morris www.rodmorris.co.nz

The walking stick insects of Ball's Pyramid.

Ball’s Pyramid is not a man-made pyramid, but the remains of a massive volcano that emerged from the sea about 7 million years ago. It juts 562 metres out of the Pacific Ocean, off the coast of Australia, near Lord Howe Island. Ball’s Pyramid is named after the British naval officer Lieutenant Henry Lidgbird Ball, who was the first European to see it
in 1788.

The island was thought devoid of life until a scientific expedition led by David Priddel and Nicholas Carlile in 2001 discovered fresh droppings of some large insect under a single melaleuca bush 30 metres up the rock face. The team went back to the site after dark and discovered a colony of 24 of the Lord Howe Island stick insect (Dryococelus australis); the species had not been seen alive for over 70 years. These insects are known as ‘land lobsters’ or ‘walking sausages’ and are 15 cm long; they are the heaviest flightless stick insects in the world.

The insects were once common on Lord Howe Island, but were presumed driven into extinction by black rats, which were introduced to the island when a supply ship ran aground on its shores in 1918. Somehow some of these wingless insects had escaped Lord Howe Island and travelled 22.5 km over open ocean to land on Ball’s Pyramid; how this happened is still a mystery.

Two years after their re-discovery, Australian officials allowed four of the species to be retrieved. One pair was given to a man who was very familiar with mainland walking stick insects; he was a private breeder living in Sydney. Unfortunately within two weeks, the pair had died. The other pair collected from the island was named ‘Adam’ and ‘Eve’ and were taken to the Melbourne Zoo and placed with Patrick Honan, of the zoo's invertebrate conservation breeding group (the image shows Patrick Honan holding two of the Lord Howe stick insects). Eve laid little pea-shaped eggs, but then became very sick. Honan developed a mixture that included calcium and nectar and fed it to Eve, drop by drop. She recovered within a few hours. Eve’s eggs were harvested and incubated, though only the first 30 were fertile. Her offspring became the zoo’s new population of walking sticks.

Jane Goodall visited the Melbourne Zoo in 2008 and Honan showed her the rows and rows of 11,376 incubating eggs. At the time, there were 700 adults in the adult population; Lord Howe Island walking sticks seem to pair off. Goodall reported that Honan showed her photos of how the walking sticks sleep at night: “…in pairs, the male with three of his legs protectively over the female beside him."

Before any of these walking stick insects can be released back onto Lord Howe Island, a massive rat annihilation programme would need to be mounted. As this annihilation project would be costly, and it’s possible not all those who live on Lord Howe Island would enjoy seeing these huge, hard-shell crawling insects back, the Melbourne Museum is considering a public relations campaign on behalf of the insect.

This video features a new baby walking stick insect emerging from its egg: http://vimeo.com/14413689#

-TEL

Read about how Ball's Pyramid formed here: http://on.fb.me/T6pPMw

http://www.npr.org/blogs/krulwich/2012/02/24/147367644/six-legged-giant-finds-secret-hideaway-hides-for-80-years; http://atlasobscura.com/place/balls-pyramid
Image credit: Rod Morris www.rodmorris.co.nz

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