Wood-Eating Cockroach Found Again After 80 Years

'The cockroach is pretty cute up close!'

Lord Howe Island wood-feeding cockroach

Justin Gilligan / NSW DPE

Long thought to be extinct, a wingless cockroach has been rediscovered in Australia when a university biology student found it under a rock underneath a banyan tree.

The Lord Howe Island wood-feeding cockroach (Panesthia lata) was once widespread across Lord Howe Island, part of an archipelago of more than two dozen islands. But since the 1930s, it was thought to have disappeared.

Maxim Adams, a student at the University of Sydney’s School of Biological Sciences, was on the island looking to see if the insects were definitely gone.

“We were simply surveying 'promising' sites to confirm that it had indeed gone locally extinct,” Adams tells Treehugger. “One such site was North Bay, where we went with the full expectation of finding nothing ... but then the first rock we turned over, there it was! It was quite an unreal feeling.”

North Bay is a secluded, white sandy beach that people can reach on foot or by water.

The researchers found families of the cockroaches under one banyan tree, but looked under every other tree and found nothing.

The metallic-looking cockroach varies in color from reddish to black and can be more than 1.5 inches (40 millimeters) long.

The Problem of Rats

The cockroach was almost erased when rats were introduced on the island in 1918.

“This has been the defining ecological challenge for the island over the last century, leading to the complete extinction of several endemic birds, as well as the near extinction of the Lord Howe Island phasmid [stick insect],” Adams says.

“The timing of the cockroach rediscovery is especially meaningful because in 2019 the managers of the island managed to completely eradicate rodents with an intensive baiting program. It really highlights the incredible benefits of their efforts!”

Some scattered populations of cockroaches were discovered on two small offshore islands in the ensuing decades after rats were introduced, but they were only close relatives.

The rediscovered cockroach is genetically different from those found earlier.

“It's amazing that one population managed to cling to life, despite over 100 years of rat predation. It reminds conservationists not to give up hope,” Adams says. “ P. lata is also a very valuable part of the island ecosystem, contributing to nutrient cycling and soil turnover; as well as a fantastic food source for many endangered birds and reptiles, which are starting to bounce back following the eradication of rats.”

A Lot of Personality

“The survival is great news, as it has been more than 80 years since it was last seen,” said Lord Howe Island Board Chair Atticus Fleming in a statement. He points out that the island is home to 1,600 native invertebrate species, half of which are found nowhere else in the world.

“These cockroaches are almost like our very own version of Darwin’s finches, separated on little islands over thousands or millions of years developing their own unique genetics,” he said.

Although conservationists and researchers are excited about the find, they realize it can be hard to get people excited about a cockroach.

“The cockroach is pretty cute up close!” Adams insists. “You'll have to take my word on it, but these guys have a lot of personality. They'll often play dead when you first spot them until the jig is up and they flee in a mad scramble. To me, there's something very special about such a simple creature managing to survive in such a remote environment, against all the odds. It's what biology is all about!”

View Article Sources
  1. "About Lord Howe." Lord Howe Island.

  2. Maxim Adams, a student at the University of Sydney’s School of Biological Sciences

  3. "Extinct' Wood-Eating Cockroach Rediscovered After 80 Years." The University of Sydney.

  4. "Invertebrates." Lord Howe Island Rodent Eradication Project.