The Alpine Flower That Eats Insects: How Scientists Finally Proved Darwin Right After 150 Years

How Scientists Confirmed Carnivory

The researchers used multiple lines of evidence to show S. candelabrum meets all four formal criteria for carnivory: attract, capture, digest, and absorb .

Field surveys and herbarium records — 43 out of 45 herbarium specimens (collected between 1888 and 2016) had trapped insects, mostly small non-biting midges, stuck to the plant's glandular hairs, proving the behavior is widespread and longstanding . Mature plants averaged 71 trapped insects .

Enclosure experiments — Plants were placed in mesh and glass enclosures to show that insects were actively attracted by scent emitted from the flowers, not merely landing accidentally .

Digestive enzyme detection — Tests confirmed that digestive enzyme activity (phosphatase) is present in the glandular hairs, allowing the plant to break down captured prey .

Stable isotope analysis — Nitrogen isotope ratios in the plant tissue matched the signature of insect-derived nitrogen, proving the plant absorbs nutrients from digested prey . Researchers fed isotope-labeled fruit flies to directly trace nitrogen-15 into the plant .

Genetic comparison — The team found that S. candelabrum shares key genes with other known carnivorous plants, including genes involved in attracting and digesting prey .

Trapping, Digestion, and Nutrient Absorption

The plant's carnivorous toolkit is surprisingly subtle:

• Attraction — The plant's flowers emit a scent that actively draws small insects, especially non-biting midges . In field experiments, blocking the scent drastically reduced insect visitation, while visual cues alone drew fewer insects .
• Trapping — The stems and branches are covered in tiny reddish glandular hairs (glandular trichomes) that secrete a sticky goo. Small insects that land on these hairs become ensnared .
• Digestion — The same glandular hairs secrete phosphatase and other digestive enzymes that break down the insect's body .
• Absorption — The plant absorbs the released nutrients, particularly nitrogen, to supplement its diet in the nutrient-poor alpine rock crevice environment where it grows .

How It Avoids Killing Its Own Pollinators

The plant appears to have evolved a clever solution to avoid "pollinator-prey conflict." The sticky glandular hairs that trap prey are located on the stems and branches — not on the flowers themselves . The captured prey are predominantly small non-biting midges, which are different from the plant's larger primary pollinators . In experiments, larger flies that visited flowers for pollination were rarely caught by the sticky hairs . Co-researcher Hang Sun noted, "The plant only targets small insects and keeps large pollinators safe" . This suggests a combination of spatial separation and size-selective trapping may be at work, though the study's specific findings on this point are limited .

Broader Implications

The discovery has several far-reaching implications:

• New carnivorous lineage — S. candelabrum is the first confirmed carnivorous plant in the order Saxifragales, showing that carnivory evolved independently in a previously overlooked plant group .
• Carnivory is more common than thought — The discovery suggests that many more plant species, especially those growing in nutrient-poor environments with sticky glandular hairs, may be undetected carnivores. The researchers recommend re-examining other sticky-haired plants .
• Confirmation of Darwin's botanical insight — Darwin predicted in his 1875 book Insectivorous Plants that certain Saxifraga species might be carnivorous based on their sticky hairs, but lacked the tools to prove it. This study vindicates his observational acuity .
• Evolutionary convergence — The genetic analysis revealed that S. candelabrum independently evolved carnivory using a similar genetic toolkit as other carnivorous plants, illustrating convergent evolution .
• Conservation relevance — Alpine and nutrient-poor ecosystems may harbor more carnivorous plants than currently recognized, which has implications for biodiversity assessments and conservation priorities .

Key source: The study was published in Nature Communications (2026), DOI: 10.1038/s41467-026-75288-y .