Eyeless wasp discovered ‘frozen in time’ in remote Nullarbor Caves
Underneath the sparse plains of the Nullarbor region in remote South-West Australia lies more than 200,000 square kilometres of caves and tunnels, formed over millions of years by seawater gradually dissolving the limestone.
The caves’ salty, dry, and dark conditions have created some of the most uniquely adapted animals in the world – perfect for the expeditions of scientists like the University of Adelaide’s Dr Jess Marsh, who is founder and conservation lead of Invertebrates Australia.
In April this year, she led a survey 1.5 kilometres deep into the caves.
“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,” she said.
Among the most recent findings of the expedition, which was undertaken by a team of researchers from the University of Adelaide and cavers from the Australian Speleological Federation, was a range of cave-adapted invertebrates, including spiders, cockroaches, and centipedes.
“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.
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Most shocking was the eyeless wasp, which is the only known example in the world to be found preserved with no functional eyes, greatly elongated legs and antennae, and extremely reduced wings – all adaptations allowing survival in the harsh cave environment.
The finding emphasises the Nullarbor Caves as a globally recognised space for biodiversity.
“I was crawling along a side passageway that was really dusty… just in front of me was this thing sat on a rock, and you get used to seeing spiders, and cockroaches, but this was a wasp, which I thought was unusual. So, I collected it, and I took it up to the surface, and a scientist colleague of mine realised it had no eyes,” Dr Marsh told InDaily.
“It was unlike any wasp I’d ever seen”.
Dr Marsh’s team at the University of Adelaide are currently conducting analysis to determine the age of the samples, which could be many thousands of years old.
Surveys of a second cave revealed a living population of a new species of spider. Large, eyeless, and slow-moving, with webs strung between rocks in the caves, their unique attributes are only found in a few cave environments across the world.
“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,” said Dr Marsh, who is also a member of the Biodiversity Council of Australia.
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“The spiders in that cave are very easy prey… they never show any signs of aggression or defensiveness,” she said.
“This makes it at very high risk of extinction. Unfortunately, the survey team also found a large amount of fox scat and a dead fox in the cave.”
With introduced species posing a threat to the native flora and fauna, the findings from the survey present an important glimpse of the complex ecosystems that exist beneath the Nullarbor Plain.
Cave system threatened
However, a recent proposal for a large-scale green energy development could pose an even bigger threat to the cave system, Dr Marsh said.
The proposal, which spans 20,000 kilometres across Western Australia up to the South Australian border, includes plans for up to 3000 turbines and six million solar panels. If approved, it would be the largest green energy development in the world, Dr Marsh said.
“Caves are really fragile environments, they’re very vulnerable to humans going in and disturbing them… we’ve got preliminary evidence that some of these spiders have disappeared from caves that have had people visiting them,” she said.
“There’s going to be roads built, along with big wind turbines where they have to drill down to put the footings in, and all of that will change the way the water moves across the landscape.”
Given the fragility of the environment and its reliance on stable humidity and water levels, the impacts of this could be extremely harmful for the caves’ ecosystems, Dr Marsh said.
“There are thousands of caves on the Nullarbor, many of which have not had scientific surveys, and our findings indicate that there may be many more weird, wonderful and scientifically important species out there,” said Dr Marsh.
“Climate change needs action, and we need green energy. But I think while addressing climate change, we have to weigh up the costs to biodiversity. If these developments result in extinctions of species, at what point do we say it’s worth it?”
