plants and animals

Australia’s tree lobsters bounced back from extinction

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Franz
Anthony

Editor and Artist
These gigantic stick insects, once a common species on its home land, were wiped out in just two years by an invasive species. 80 years later, the last living population of the species is discovered in an unlikely place across the waters.

For centuries, on Lord Howe Island, 600 km (370 mi) away from mainland Australia, lived one insect species so large, it was nicknamed the ’tree lobster’. At 12 cm (5”) long, these flightless, armored insects once thrived in abundance, the locals would use them as regular fishing baits.


In an unfortunate day in June 1918, a British supply ship SS Makambo ran aground near Lord Howe Island. In the span of nine days when the crews repaired the ship, black rats managed to sneak out of the ship and moved onto the island. This invasive species immediately outcompeted the island’s native fauna, driving several species to extinction including various endemic birds. Fast forward two years after the incident, not a single stick insect was seen on the island. This once so common species was completely wiped out in such a short time.


21 km (13 miles) away from Lord Howe Island, stood a peculiar spire of rock. The Ball’s Pyramid is an erosional remains of an old volcano which existed about 6.4 million years ago. Little did people know, this rock became the last bastion of the insects, harboring the last thriving population ever found.


In the 1960’s, some climbers who visited Ball’s Pyramid reported that they had seen fresh corpses of the insects on the rocky island. A few more dead insects were discovered by subsequent expeditions, but nobody could find a living specimen of the nocturnal insect.


It wasn’t until 2001, when two Australian scientists discovered a deposit of large insect droppings under a single shrub 100 m (330’) above the sea. The duo then returned after dark with a local ranger, assuming that the insects probably lived under this shrub. Indeed, under a pile of plant debris beneath the shrub, the team discovered 24 specimens of the enormous insect thriving in such an unlikely barren chunk of rock far away from their home land. Nobody knew how the flightless stick insects managed to get there in the first place.


Everybody knew, though, that it was the last breeding population of the insects, and they had to be protected. After rigorous studies, government officials granted the permission to retrieve two breeding pairs from the rocks to be bred in captivity for future reintroduction programs. But this effort was not without challenges, as the first breeding pair immediately died within two weeks.


The other pair, nicknamed “Adam” and “Eve,” were taken to the Melbourne zoo where they successfully laid eggs under the watch of Patrick Honan. When Eve got very sick, Patrick instinctively fed her a mixture containing calcium and nectar, nursing her back to full health. 30 of her eggs were found to be fertile, and the offsprings eventually became the foundation of the zoo’s breeding program. As of April 2012, the zoo’s population quickly soared to 1,000 adult insects and 20,000 eggs.


This story, however, is just the beginning. The rats, which caused the mass extinction to happen in the first place, are still thriving on the island. To successfully return the insects to their homeland, an extensive eradication program is necessary. In addition, not every resident of the island is ready to welcome back their six-legged neighbors who have been absent from the island for more than half a century, prompting the Melbourne Museum to launch a campaign to promote the species. At the very least, the breeding program seemed to succeed and it’s only a matter of time before the insects are reintroduced to the island.


Original findings published in NPR.

Image Credit: Granitethighs on wikimedia

8e6ac47821297aeee8c843e680637dca

Franz
Anthony

Editor and Artist


http://sulc.us/4klni
http://www.eartharchives.org/articles/six-legged-giant-finds-secret-hideaway-hides-for-80-years/