lord-howe-islands

Rare Stick Insect Hatchling

This chartreuse green insect is unfurling from its little egg to add to a slowly swelling captive population of Lord Howe Island stick insects – one of the rarest, and largest, insects in the world – at Melbourne Zoo. It will grow up to be a flightless, nocturnal insect that stretches up to 12 cm long, its solid, shiny black or rust-colored body weighing up to 25 grams.

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THE INSECT THAT CAME BACK TO LIFE

By 1920, the Lord Howe Island stick insect (Dryococelus australis) was thought to be extinct as a result of rats being introduced to the island. Over 80 years later, in 2001, however, two Australians scientists discovered a group of 24 of these large stick insects.

Since the discovery, the insects have been successfully bred in captivity at Melbourne Zoo. As of 2012, the population of the Dryococelus australis has reached over 9,000 individuals, with thousands of eggs waiting to hatch. The ultimate goal is to place the insects back on their home island, after the planned eradication of rats.

These stick insects live for about 2 years and measure up to 15 cm (6 inches). The nymphs are green and diurnal, and turn black and nocturnal as they become adults. Today, they are still considered critically endangered.

Image credits: 1, 2.

BALL’S PYRAMID

Ball’s Pyramid is not a man-made pyramid, but the remains of a basaltic shield volcano that emerged from the sea less than 7 million years ago. It is 562 metres high and 1,100 metres in length, making it the tallest volcanic stack in the world. It juts out of the Pacific Ocean, off the coast of Australia, 20 kilometres southeast of 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 is comprised almost entirely of nearly horizontally-bedded lava flows which are the remains of a volcanic plug from a former vent of a volcano. Potassium-argon dating indicates that it is around 6.4 million years old, a similar age to Mount Gower and Mount Lidgbird on Lord Howe Island. After the eruption of the shield volcano, erosion saw the volcanic slopes form a submarine shelf. Ball’s Pyramid is in the centre of this shelf, forming a platform 20 km in length from north to south and around 10 km wide. The average water depth is about 50 metres. Lord Howe Island sits in the middle of a slightly larger shelf; the platforms of the two shelves are separated by a 500 metre deep canyon. Wave erosion will eventually truncate the volcanoes. 

Both Ball’s Pyramid and Lord Howe Island are part of the Lord Howe Rise, which in turn is part of the submerged continent of Zealandia. Lord Howe Rise is a remnant of continental crust in the Tasman Sea, on the Australian plate.

The first successful climb to the summit of Ball’s Pyramid was made by a team of climbers from the Sydney Rock Climbing Club on 14 February 1965. Another team, led by Dick Smith, reached the summit in 1979 and unfurled a New South Wales flag, declaring the island Australian territory. Climbing was banned in 1982 and in 1986 all access to the island was banned. In 1990, the policy was changed to allow some climbing under certain conditions.

Ball’s Pyramid was thought devoid of life until a scientific expedition led by David Priddel and Nicholas Carlile in 2001 discovered a colony of 24 Lord Howe Island stick insects (Dryococelus australis) under a single melaleuca bush 30 metres up the rock face. 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. A pair of the insects was sent to Melbourne Zoo which successfully operated a breeding programme; over 700 of the insects exist today. Read more about these insects and the breeding programme here: http://on.fb.me/ZHIVup.

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http://serc.carleton.edu/vignettes/collection/35376.htmlhttp://www.uq.edu.au/nuq/jack/climbing/bp.htmlhttp://www.uq.edu.au/nuq/jack/Bryden.html
Image credit: Fanny Schertzer

Balls Pyramid | ©John Lenagan  (Lord Howe Island, Australia)

Balls Pyramid is a 560m volcanic stack rising vertically out of the ocean 22 km south of Lord Howe Island.

The Lord Howe Island Group is an outstanding example of oceanic islands of volcanic origin containing a unique biota of plants and animals, as well as the world’s most southerly true coral reef. This place is recorded by UNESCO as a World Heritage Site of global natural significance. Lord Howe Island is located 660km off the east coast of Australia.