Lord Howe stick insect: A triumph over extinction adversity
The incident with the SS Makambo ship in 1918 led to an unforeseen ecological disaster. Rats that escaped from its deck onto Lord Howe Island quickly dominated the local environment, eliminating species lacking natural predators. One of their victims was the stick insect Dryococelus australis, also known as the Lord Howe Island stick insect.
For decades, it was believed that the stick insect became extinct around 1920. It wasn’t until 2001 that scientists, Dr. David Priddel and Dr. Nicholas Carlile, discovered a small population of this species during an expedition to Ball’s Pyramid—a rocky outcrop located in the Tasman Sea, distant from Lord Howe Island. It turned out that the insects survived in extreme conditions, benefiting from protection from rats, provided by their presence on the rock remote from the island. The ability of females to reproduce without males (parthenogenesis) contributed to their survival, reports Earth service.
The world's rarest insect returns
In 2003, two individuals belonging to the Dryococelus australis species, named Adam and Eve, arrived at the Melbourne Zoo to initiate a breeding program. After initial difficulties, they managed to breed them, which allowed the insects to be sent to other zoos around the world. Their return to Lord Howe Island was also planned, but the key to the success of this project was the elimination of the rats and mice living there.
Rodents reached the island after the SS Makambo ran aground in June 1918 near Neds Beach, at the northern tip of the island. The ship was relaunched after 9 days. During this time, the rats escaped from its deck and reached the land. Black rats, a species found on all continents except Antarctica, quickly took over the island and affected its ecosystem. Their victims included numerous bird and insect species, including the aforementioned Dryococelus australis—currently considered the rarest insect in the world.
Only through a comprehensive rodent eradication campaign in 2019 was the island "freed" from these pests, although—as noted by the Earth service—in 2021, there were a few cases of their presence, requiring additional measures. Today, thousands of Lord Howe Island stick insects are bred in captivity, ready to return to their original homeland. Biologists emphasize that the restoration of this species is an ecological success and an example of the importance of protecting fragile ecosystems from invasive species.
