The Lord Howe Island cockroach ( Panesthia lata ), is a species of cockroach without wings but of considerable size, which disappeared from its island of origin after the introduction of ship rats (Rattus rattus) in 1918 . Now, it has been rediscovered by biologists at the University of Sydney, Australia.
For a long time it was thought that it had become completely extinct as a result of this event. It hasn’t been seen since the 1930s, but a biology student at the Australian university, Maxim Adams, spotted families of cockroaches under a banyan tree earlier this year and it turned out to be these wood-chewing insects.
The Lord Howe Island wood-feeding cockroach is between 2.2 and 4 cm long and has a metallic body color that varies from reddish to black. Mind you, while scattered populations of close relatives were discovered on two small offshore islands, the rediscovered group was genetically different from those. This is the original species.
The invasive rats, although they spread across the island, do not seem to have wiped out the species.
“Its survival is great news as it has been over 80 years since it was last seen,” Lord Howe Island Board Chairman Atticus Fleming said. “Lord Howe Island is truly a spectacular place, it is older than the Galapagos Islands and is home to 1,600 native species of invertebrates, half of which are found nowhere else in the world. These cockroaches are almost like our own version of Darwin’s finches, separated on small islands over thousands or millions of years, developing their own unique genetics.”
The value of these insects in the ecosystem should not be underestimated. It is practically the cornerstone of the health of the island. Cockroaches have specialized microorganisms in their intestines that allow them to eat decaying wood. They are like “nutrient recyclers” that help in the decomposition of tree trunks. Therefore, they accelerate the decomposition of the logs and also serve as a food source for other species.
Rock cockroaches, more appropriate
“Although their common name suggests they are wood-eating cockroaches that burrow into rotten logs, we now believe they are more like ‘rock cockroaches,’ with rocks being an important component of their habitat, possibly due to its co-evolving alongside the Lord Howe Island wood fowl ( Hypotaenidia sylvestris ) which forages on the ground,” said Nicholas Carlile, a researcher at the NSW Department of Planning and Environment.
The researchers intend to study the hardy cockroaches to learn more about their habitat and activities and how they managed to survive.
“There is still a lot to learn. We hope to study their habitat, behavior and genetics, and learn more about how they managed to survive, through more experiments on the island,” said Nathan Lo, a professor at the University of Sydney.
Reference: University of Sydney (Australia) Press Release 2022
