Scientists discover a flower that secretly eats insects, and say there could be many more killer plants

For more than a century, botanists believed that only a small group of plants had evolved to eat insects. But a new study suggests that list may be far from complete. Researchers have confirmed that Saxifraga candelabrum, an alpine flowering plant found in China's high mountains, is a true carnivorous plant—and say many other species previously dismissed as merely "sticky" could possess the same hidden appetite.

The findings, published in Nature Communications, show that Saxifraga candelabrum attracts insects with scent, traps them using sticky glandular hairs, digests them with specialized enzymes and absorbs nutrients from their bodies, fulfilling all the criteria required to classify a plant as carnivorous.

A mountain flower with a hidden appetite

Unlike famous carnivorous plants such as the Venus flytrap or pitcher plants, which typically grow in nutrient-poor wetlands, Saxifraga candelabrum survives in rocky alpine habitats between 8,200 and 10,800 feet on the Qinghai-Tibet Plateau and China's Hengduan Mountains.


Researchers observed that mature plants routinely trapped dozens of tiny gnats on the sticky hairs covering their flowering stems, with some specimens capturing as many as 70 insects.

Experiments revealed that the flowers lure prey using scent rather than visual cues. Once trapped, the insects are broken down by the digestive enzyme phosphatase, allowing the plant to extract valuable nutrients.

To confirm that the nutrients were actually absorbed, scientists fed the plants insects labelled with the stable isotope nitrogen-15. The isotope later appeared inside the plant tissues, providing direct evidence that the flower was feeding on its prey rather than simply trapping it.

It knows what not to eat

One of the study's most surprising findings was that the plant appears selective about its meals.

Tiny gnats became trapped in the sticky hairs, but larger flies that pollinate the flowers were rarely caught. This allows the plant to obtain nutrients without sacrificing the insects it depends on for reproduction.

Why would a plant evolve to eat insects?

Carnivorous plants generally evolve in places where soil contains very little nitrogen, an essential nutrient for growth.

"Insect prey is rich in nitrogen," study co-author Douglas Soltis of the Florida Museum of Natural History and the University of Florida explained.

"When the soil is low in nitrates this is one adaptation that has emerged."

The discovery is especially unusual because almost all known carnivorous plants inhabit bogs or wetlands. Saxifraga candelabrum instead thrives in dry, rocky alpine terrain, making it the first confirmed carnivorous plant adapted to this type of mountain environment.

Scientists think this may be just the beginning

The researchers believe the discovery could dramatically change how botanists search for carnivorous plants.

Many flowering plants possess sticky glandular hairs that have traditionally been viewed as a defense against herbivores. But the new findings suggest some of those species may also digest insects and absorb nutrients without anyone realizing it.

"Some species of the plants previously only known to bear sticky glandular hairs or trap insects incidentally may actually have undiscovered digestive and nutrient absorption capabilities," said senior study author Hang Sun of the Kunming Institute of Botany.

He added that carnivory may be far more widespread among flowering plants than scientists currently believe.

Today, botanists recognize more than 350,000 species of flowering plants, yet only about 750 are officially classified as carnivorous. Because carnivory has evolved independently at least 14 times, researchers believe additional carnivorous lineages could still be waiting to be discovered.

A 151-year-old prediction finally confirmed

The study also resolves one of botany's oldest unanswered questions.

In 1875, Charles Darwin proposed that sticky hairs on members of the Saxifraga genus might help the plants trap and consume insects. Although he suspected they were carnivorous, the scientific tools available during his lifetime could not prove it.

More than 150 years later, modern techniques—including isotope tracing, enzyme analysis and genome sequencing—have finally confirmed that Darwin's intuition was correct.

For the researchers, however, the discovery is less about settling a Victorian-era hypothesis and more about opening the door to new discoveries.

If one familiar flowering plant managed to hide its carnivorous lifestyle for over a century, scientists say many more may still be waiting in plain sight.