A scientific mystery that began with Charles Darwin’s observations in the 19th century has finally been solved. Researchers have confirmed that a small flowering plant from China’s mountains is a true carnivorous species, proving a theory Darwin first proposed more than 150 years ago.
The discovery offers new insight into plant evolution and suggests that more insect-eating plants may still be waiting to be identified around the world, including potentially in Canada.
Scientists Confirm Carnivorous Behaviour in Mountain Plant
Researchers have identified Saxifraga candelabrum as a carnivorous plant that captures and consumes insects using sticky hairs covering its leaves and stems.
The study, published in Nature Communications, confirms suspicions first raised by Darwin in 1875 when he noticed insects trapped on certain plants belonging to the Saxifraga genus.
University of Florida botanist Douglas Soltis, one of the study’s authors, said Darwin would likely have been fascinated by the findings.
“I hope he’d be really excited and wanted to give us a big high five or two thumbs up,” Soltis said. “I’m imagining him smiling right now.”
The research team showed that the plant does more than simply trap insects. To be classified as carnivorous, a plant must be able to digest its prey, absorb nutrients and distribute those nutrients throughout its body.
Sticky Hairs Help Plant Capture Insects
Saxifraga candelabrum grows in rocky mountain crevices in southwestern China, where soil conditions provide limited access to essential nutrients.
The plant is covered with tiny hairs that produce a sweet, sticky substance. The scent attracts insects, which then become trapped on the plant’s surface.
“You’ll just see insects plastered to the leaves and stems of these plants,” Soltis explained. “And so it just makes you wonder: What are they doing with all those insects?”
Darwin made similar observations more than a century ago but lacked the technology needed to prove whether the plants were actually feeding on their trapped prey.
Modern laboratory techniques allowed researchers to track nutrient movement inside the plant. Scientists used fruit flies raised on food containing a stable form of nitrogen, allowing them to follow how the nutrient was absorbed.
Why the Plant Eats Insects
According to researchers, the plant is not consuming insects for energy but to obtain nitrogen, a vital nutrient that is difficult to access in its mountain environment.
“Plants don’t need carbon. They’re able to make that,” Soltis said. “But they really need nitrogen.”
Most carnivorous plants are commonly found in wetlands and bogs, where acidic, waterlogged soil often lacks essential nutrients. However, Saxifraga candelabrum demonstrates that insect-eating strategies can also evolve in dry, rocky habitats.
Peter Ryser, a plant ecologist at Laurentian University in Sudbury, Ontario, said the plant may have developed its sticky hairs for protection before eventually adapting them for nutrition.
The hairs may have originally helped prevent insects from damaging seeds, but over time, the plant may have evolved the ability to extract nutrients from trapped insects.
Balancing Insect Traps and Pollination
Carnivorous plants face a unique challenge: they need insects for food but also depend on some insects for reproduction.
Researchers found that Saxifraga candelabrum appears to avoid harming important pollinators by mainly trapping smaller insects.
“They trap a smaller type of insect, and then larger insects that are the pollinator are not really affected by these hairs,” Soltis said.
This balance allows the plant to gain nutrients while maintaining its ability to reproduce.
Discovery Could Lead to More Carnivorous Plants
Scientists believe the discovery could indicate that other unknown carnivorous plants may exist.
Researchers at the University of British Columbia previously identified a plant growing in Cypress Provincial Park that uses a similar insect-trapping method, showing that carnivorous behaviour is not limited to tropical or exotic species.
UBC botanist Sean Graham said the latest findings support earlier predictions that more examples of plant carnivory could eventually be discovered.
“I’m sure there are other examples of plant carnivory out there, waiting for discovery,” Graham said.
According to the Natural History Museum in the United Kingdom, more than 630 carnivorous plant species are currently known worldwide. These include Venus flytraps, which close their leaves around insects, and pitcher plants, which use nectar to lure prey into digestive fluids.
Canada is also home to several carnivorous plants, including pitcher plants found in wetlands across parts of the country. Some have even been observed consuming small animals such as salamanders.
A Darwin-Era Mystery Finally Solved
The confirmation of Saxifraga candelabrum as a carnivorous plant closes a scientific question that remained unanswered since Darwin’s time.
Researchers say the discovery highlights the remarkable ways plants have evolved to survive in challenging environments and suggests that nature may still hold many hidden examples of plants that have adapted in unexpected ways.
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