Since the 1930s, nobody had observed the Lord-Showe-Kakerlake called Panesthia Lata-until the biologist Maxim Adams from the University of Sydney came to the island. "In the first ten seconds I thought" No, that couldn't be ". After all, it was the first stone that I had raised under this huge Banyan tree, and there was, ”reports Adams, who, together with his team, succeeded in rediscovery in July 2022. Under the tree mentioned, the group later rejected entire families of the insect.
Until 1918, the species on the Australian Pacific Island of Lord Howe was widespread, but when house rats conquered the island after a shipwreck, these insects quickly disappeared like many other species. Over the next few decades, scattered populations were discovered by nearby relatives on two tiny islands off the coast. But the group on Lord Howe differs genetically from them.
The wingless cockroach grows up to 40 millimeters in length and has a metallic body color that varies from reddish to black. It is one of eleven species of Panesthia wood cockroaches in Australia: powerful cave dwellers that live in the rainforest and open forests in the northern and eastern coastal areas of Australia and feed on rotted trunks. For this purpose, they harbor special microorganisms in their intestines, which help digest the cellulose in the wood.
"Although your common name suggests that it is wood -decomposing cockroaches that dig into rotting tree trunks, we now believe that they are more of a" rock cockroach "," says the biologist Nicholas Carlile, which is involved in the study. There they are better protected from the Lord-Showe rouven (Gallirallus Sylvestris) who are looking for food in the ground and undergrowth. It could therefore be an adaptation to the special conditions in the spatially restricted island ecosystem.
Since the insects again enter valuable nutrients from the wood into the landscape over their feces, scientists had considered to suspend animals from the offshore islands. But that should be unnecessary. Various campaigns are likely to have contributed to the survival of the insects, in which introduced animals were eradicated again: In addition to the rats, overgrown pigs, goats and cats, of which the rallen also benefited from the cockroaches.
The most famous example of a disappeared insect of Lord Howe are the giant tree lobsters (Dryococelus australis). In fact, they only survived on a tiny rock in the sea called Ball's Pyramid; after their discovery, they were bred 100 times in zoos. After the restoration of the ecosystem on Lord Howe, these insects are to return to their original homeland.
