27-06-2025
60-year mystery of Aussie plant finally cracked by scientists
Australian scientists have gone to great lengths to crack a decades-long mystery of how a native plant that has continued to grow and thrive in a patch of land in Western Australia, with the answer under their noses all along.
There are 130 known species of boronia across Australia and New Caledonia, with the majority easily recognisable from their pretty, open-petalled flowers. However, 18 species growing in a triangle between Kalbarri, Augusta and Esperance in WA have all boasted "weird and wonderful" flowers that are closed off to most pollinators. How the plant continues to spread stumped scientists for over 60 years.
"The location has a spectacularly diverse ecosystem, and it's a really special place from an ecological viewpoint," Doug Hilton, scientist and CEO of CSIRO, told Yahoo News. "The weird flowers of these boronias have suggested to scientists for over 60 years that there must be pure pollinators of the plants. It couldn't have evolved that way by accident."
This 'pure pollinator' — an animal or insect that exclusively pollinates a plant — has been elusive to scientists for decades. But for the last 15 years, Doug and his team have been tirelessly working to prove a theory.
Over 60 years, scientists who have encountered the boronia species have made suggestions on who the mystery pollinator could be, and different insects have been hypothesised.
"If you look in the scientific papers, there's an occasional reference to a moth, but nothing ever came of it. They had never been collected systematically or photographed," Doug explained.
One of the reasons why the moth species called Heliozelidae was never previously pursued was because, unlike many other types of moths, they fly during the day. They are seldom attracted to lights, so they're underrepresented in museum collections. The best way to collect and study them is to sweep a butterfly net over plants and look inside — literally. Images show Doug standing in Western Australia with his head inside a butterfly net.
"We found they had the right structure at their abdomen that collects the pollen of the boronias, and these structures are like nothing that has been seen in the other 150,000 species of moths and butterflies; they're absolutely unique," he said. "It was a real Eureka moment."
The moths and the boronias have an 'obligate mutualism', meaning they both rely on the other to survive.
"It's great for the moth because she can pollinate the plants, and her caterpillars have food, and therefore the species survives as she passes on her genes. And it's good for the plant, because they now have a very efficient pollinator... it's all about balance," he said.
Doug continues to study the insects to further deepen the evidence that they are responsible for the plants, and explained a discovery like this is the reason he became a scientist in the first place.
" I think that scientists have an obligation to talk to the community about the work they do, and I think there's an appetite for people to understand the wonder of the world," he said. "There's a lot of bad news and a lot of pessimism in the world right now. I think if you can begin to understand how the world works, and do it through science, that's really valuable."
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