We like to bring you the occasional large invertebrate on this blog. And even a huge vertebrate now and then. But here’s a big insect with a story to tell. And it’s a story that hasn’t – quite – ended yet.
The Lord Howe Island Stick Insect, or Tree Lobster, Dryococelus australis, is one of the largest insect species in the world. It is a flightless phasmid that lives on trees in the isolated Lord Howe Island chain off the Australian coast. These great creatures were once common enough to be used regularly as fishing bait, but in 1918 a supply ship ran aground there and accidentally introduced the black rat. By 1920 the tree lobster was thought to be extinct, a casualty of the voracious rats which cut a swathe through the native island ecosystem. Hopes that the animals had survived were rekindled when newly dead specimens were found by climbers in the 1960s on an isolated islet nearby called Ball’s Pyramid. Living specimens were found in February 2001 – but only 24, living on a single bush 500 feet up a sheer cliff-face. After much soul-searching, four individuals were taken for a breeding programme which eventually succeeded after considerable difficulties. It seems that these insects, unusually, pair for life, with the males and females living together.
Even so, there were doubts as to whether these were, in fact, the long-lost insects or not. The captive individuals looked different to the old museum specimens, and it had been a very long time since any others were seen. It took ten years and a DNA sequencing investigation to demonstrate that the Melbourne captive population was indeed the same species as the long-lost Tree Lobster.
Today there are about 450 individuals in captivity at Melbourne Museum, and consideration now arises about whether, and how, they could be returned to their original habitat of Lord Howe Island, and what to do about the rats. That’s the current question, and as yet, the reintroduction hasn’t gone ahead. Robert Krulwich writes:
Residents would, no doubt, be happy to go rat-free, but not every Lord Howe islander wants to make the neighbourhood safe for gigantic, hard-shell crawling insects. So the Melbourne Museum is mulling over a public relations campaign to make these insects more… well, adorable, or noble, or whatever it takes. They recently made a video, with strumming guitars, featuring a brand new baby emerging from its egg. The newborn is emerald-green, squirmy and so long, it just keeps coming and coming from an impossibly small container. Will this soften the hearts of Lord Howe islanders?
Article updated with National Geographic report October 2017.