When small species are left alone to evolve for centuries on small islands, they often become larger. Quietly, over thousands of years, Dryococelus australis grew to a great size on Lord Howe Island, in the Tasman Sea between Australia and New Zealand.
But the peaceful life of the Lord Howe Island stick insect, an invertebrate of such gargantuan proportions that it is also fondly known as the tree lobster, was destroyed by European settlers. In 1918, a shipwreck brought black rats to the island. The flightless insects were once so common they were used by settlers as bait for fishing, but the rats wiped out the entire population on the island in just two years.
In 1964, a group of climbers attempting to scale Ball’s Pyramid, a spectacular pinnacle of basalt jutting from the ocean 20km (12 miles) off the coast of Lord Howe Island, discovered and photographed the sausage-sized carcass of one of the insects. They failed to reach the top but subsequent climbing attempts found more stick insect bodies – just never a live one.
Tantalised by these sightings, in 2001, the Australian scientists David Priddel and Nicholas Carlile made their way to the island. At first they discovered large insect droppings under a single shrub growing in a crevice on a steep slope 100 metres above the shoreline. Returning after dark, when the insects are active, they found three live females living beneath the single shrub.
“I was lost for words, except for the odd expletive,” Carlile said at the time. “We couldn’t jump for joy for fear of falling off the 60-degree slope.”
The next year, 24 were discovered and a breeding pair were taken to Melbourne Zoo. Eventually, the species was successfully bred in captivity. Thousands of stick insects have now been reared in six zoos around the world. There are plans for reintroductions on another islet and ultimately back in Lord Howe Island itself, where the invasive black rat and house mouse population was confirmed as eradicated in 2025. (This eradication programme was more successful than an attempt after the initial rat invasion of 1918 when the authorities offered a bounty for each killed rat and later discovered the Lord Howe Islanders had been breeding the rats to claim more bounties!)
Still one of the rarest invertebrates in the world, with possibly only 50 insects enduring in the wild, this year scientists found additional individuals hidden in sparse vegetation on Ball’s Pyramid.
This inspiringly tenacious, super-sized, rock-dwelling tree lobster, which grows to as long as 20 centimeters (6 to 8 inches) as an adult, has multiple nominations from Guardian readers around the world. Its rediscovery and flourishing is a sorely needed story of hope, according to Maximilian Vanlancker from Seattle. “Climate change is rampant, fascism on the rise, corporate greed uncontrolled, but despite it all, those 24 stick insects on a rock show us that it is never over until we give up.”
I’ve got a big soft spot for this huge insect. As a young journalist at the turn of the century, dispatched to be the then solitary Guardian representative in Australia, the rediscovery of this marvellously resilient creature was one of my first front-page stories. I still remember the headline: The Walking Sausage Lives Again.
-
It’s invertebrate of the year again! From 3-12 August, every day we’ll be profiling one of the thousands of amazing invertebrates that our readers have nominated, and then, when you’ve got to hear about all of them, we’ll open the voting so you can choose your favourites. Don’t hesitate to get in touch with thoughts and ideas: email us at environment.desk@theguardian.com with Invertebrate in the subject line
