A team of researchers from the University of Adelaide, in collaboration with cavers, has uncovered a remarkable trove of eyeless, cave-adapted invertebrates beneath the Nullarbor Plain. The discoveries include spiders, cockroaches, centipedes, and a wasp that is physically evolved for life in total darkness.
The wasp discovered is the only known species worldwide to exhibit such dramatic adaptations for life in complete darkness. It is completely blind, with no functional eyes, has highly reduced wings, and exceptionally long legs and antennae. "The adaptations of the wasp are an extraordinary testament to evolution's creativity in the most extreme environments," noted Dr. Jess Marsh from the University of Adelaide, who led the survey.
"The cave contains thousands of such invertebrates. Some, bizarrely, had died mid-way through climbing the cave walls—caught frozen in time," said Dr. Marsh, according to Phys.org. All the invertebrates were already dead when discovered. The bodies were mummified and exceptionally preserved by the arid conditions. Some of the species may already be extinct, and the team is working to determine the age of the specimens, which could range from decades to thousands of years.
Many of these species are new to science. The researchers are also working to uncover why only dead invertebrates were found in the first cave. The mummified bodies offer a unique opportunity to study these organisms and their adaptations to extreme environments.
In a second cave, the team discovered a living population of what is likely a new species of large, eyeless spider. These spiders are pale, slow-moving, and graceful. They build very large webs in caves, which they string between rocks. "The new spider species is found only in this location," said Dr. Marsh. "Each of the currently described species of these spiders are only known from single caves, and it is possible that this new species may only occur in this one cave. This makes it at very high risk of extinction."
Evidence of foxes in the cave, including a large amount of fox scat and a dead fox, has raised concerns about the impact of invasive predators on these rare spiders. Research is ongoing to find out whether foxes prey on these spiders. The presence of invasive species poses a threat to the delicate ecosystem within the caves.
The expedition saw researchers and cavers from the Australian Speleological Federation travel over 1.5 kilometers through challenging cave terrain beneath the Nullarbor Plain. "The long journeys into these caves were incredibly challenging—filled with tight squeezes, a lot of time spent crawling, and belly-wriggling through dusty sediment, plus a few nerve-wracking heights. But I would repeat it in a second," said Dr. Marsh, a founder of Invertebrates Australia.
Dr. Marsh described the caves as having "otherworldly beauty" and "the sheer magnificence of the stalactites, stalagmites and other structures," noting the remarkable biodiversity. The discoveries reveal the unique biodiversity of the Nullarbor caves, providing an important glimpse into the past and present ecosystems of the region.
"The discoveries suggest that there may be many more rare species remaining to be found in the region's unexplored cave systems," said Dr. Marsh.
Some of the Nullarbor caves are threatened by proposed green energy developments. The discoveries underscore the area's importance for biodiversity and the need to protect these unique environments. The team hopes that their findings will bring attention to the conservation needs of the region.
The researchers plan to continue their exploration and study of the Nullarbor caves, hoping to uncover more of the secrets that lie beneath the surface.
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