Island Removes Rats, 60% More Insects Return in 5 Years

Ancient beetles with iridescent green wings are swarming through the treetops of Lord Howe Island again, looking for mates under the summer sun. Just ten years ago, naturalist Ian Hutton would have struggled to spot even one.

The remote island, sitting 600km off Australia's east coast, is home to over 1,600 different invertebrate species. Half exist nowhere else on Earth, thriving in forests that feel "ancient" and "otherworldly," like something from Jurassic Park.

But in 1918, everything changed when a supply ship ran aground and rats jumped off, joining mice that had arrived decades earlier. Together, the rodents ate their way through the island's treasures, pushing five bird species, two plants, and at least 13 invertebrate species to extinction.

In 2019, Lord Howe fought back with a bold eradication program that removed roughly 300,000 rats and mice from the 15 square kilometer island. Scientists had the foresight to count and catalog the bugs beforehand, creating a baseline to measure recovery.

Now the results are in. A new study in Biological Invasions reveals that invertebrate populations have jumped 60% across the island's sites.

"I think that's pretty extraordinary," said researcher Maxim Adams from the University of Sydney. "Walking around Lord Howe now, all of us are blown away by what we're seeing."

The Ripple Effect

The bug boom is triggering cascading benefits throughout the entire ecosystem. Birds and geckos are feasting on the abundant insects, with the island's unique ground-nesting woodhen population steadily climbing.

Forest understories that had vanished are regenerating as seeds finally get a chance to sprout without rodents devouring them. Hundreds of seedlings are pushing through the soil.

The Lord Howe Island cockroach, once feared extinct, is thriving again. A stag beetle species unseen for over a century turned up during a camping trip when Hutton went bug collecting at night.

Adams believes this is just the beginning of a recovery that could take decades to fully unfold. "Almost every part of the ecosystem is going to benefit," he said, predicting gains in bird numbers, reptile populations, and even soil health.

On night walks with tourists now, Hutton finds striking beetles and snails everywhere he looks. The island's food web, unusual because it evolved without native mammals, is reorganizing itself into something healthier and more balanced.

What was lost over a century is finally coming back, one beetle at a time.