Charles Darwin has been proven right 151 years after first theorizing that Saxifraga candelabrum uses sticky hairs to trap and devour insects, according to a study published Tuesday in Nature Communications. University of Florida botanist Douglas Soltis and his research colleagues confirmed that the flowering plant growing in southwestern China’s rocky mountain crevices operates as a stone-cold killer, absorbing vital nitrogen from its prey.
How Researchers Proved Darwin’s 1875 Plant Carnivory Theory
Charles Darwin first suspected carnivory within the Saxifraga genus in 1875, according to historical accounts noted by University of Florida botanist Douglas Soltis. Back then, the English naturalist observed tiny insects stuck to the leaves and stems of two European plant varieties but lacked the modern technology required to prove digestion and nutrient absorption.
To establish proof, the research team fed fruit flies a diet enriched with a stable, radioactively labeled form of nitrogen. According to Soltis, scientists used medical-style tracing techniques to watch the labeled materials flow throughout the plant’s body after the insects became trapped on the millimetre-long hairs.
Did you know? While pitcher plants and Venus flytraps are famous meat-eaters, the carnivorous plant catalog spans more than 630 species worldwide, with researchers continuously finding hidden predators in unexpected botanical families.
Why Nutrient-Starved Mountain Plants Turn to Flesh
Saxifraga candelabrum targets insects specifically for nitrogen rather than carbon, which the yellow-flowering plants can generate on their own, according to botanist Douglas Soltis. Growing in nutrient-poor spoil across rocky mountain crevices, these specimens face harsh growing conditions similar to those of bog and wetland carnivorous plants.
Plant ecologist Peter Ryser of Laurentian University in Sudbury, Ont., who was not involved in the study, notes an evolutionary path where species likely first evolved sticky hairs to deter seed-eating pests. Over time, these plants adapted to secrete enzymes and extract nutrients from the insects stuck to their stems.
Balancing Carnivory and Pollination in the Wild
Carnivorous plants face an inherent survival conflict: they need to capture prey for sustenance while simultaneously attracting pollinators to reproduce. Saxifraga candelabrum resolves this challenge by selectively trapping smaller bugs while leaving larger pollinating insects, such as flies, unharmed, according to University of Florida botanist Douglas Soltis.
This targeted trapping mechanism ensures the species can feed on nitrogen-rich insects without disrupting the ecological partnerships required for reproduction.
More Hidden Carnivorous Plants Awaiting Discovery
The latest findings suggest that additional carnivorous plants remain hidden in plain sight within Darwin’s beloved Saxifraga genus and beyond, according to study authors. Five years prior to this publication, researchers at the University of British Columbia discovered a plant in B.C.’s Cypress Provincial Park utilizing a comparable trapping method.
“At the time, we predicted that additional examples of carnivory would be discovered, and so it was really gratifying to read this paper and see our predictions coming true,” UBC botanist Sean Graham told CBC in an email. Graham added that he expects further examples of plant carnivory to surface through ongoing research.
Frequently Asked Questions
How do carnivorous plants like Saxifraga candelabrum catch insects?
They utilize millimetre-long hairs on their leaves and stems that produce a sweet, scented, and sticky substance to lure and trap unsuspecting insects, according to University of Florida botanist Douglas Soltis.
Why do these plants eat insects?
They consume insects primarily to obtain essential nitrogen from nutrient-poor soil environments, rather than for carbon, which they produce independently, according to Douglas Soltis.
Did Charles Darwin know about carnivorous Saxifraga plants?
Yes. Darwin first theorized in 1875 that members of the Saxifraga genus were carnivorous after observing insects stuck to their leaves, though he lacked the technology to prove digestion at the time.
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