Darwin vindicated as alpine Saxifraga candelabrum shown to trap and digest midges

A recent study confirms Charles Darwin's 1875 prediction that the small alpine plant Saxifraga candelabrum can capture and digest insects. Researchers report that its glandular hairs secrete a sugary adhesive that lures midges and an enzyme that breaks them down.

Researchers have confirmed that Saxifraga candelabrum, a diminutive alpine plant first noted by Charles Darwin in the 19th century, is capable of trapping and digesting small insects. The finding supports Darwin’s 1875 suggestion that the species might be insectivorous and adds to the catalogue of plant carnivory known to science.

Sticky traps and digestion

The plant’s leaves, petals and stems are densely covered with tiny glandular hairs that exude a sweet, sticky substance. The adhesive both attracts and immobilises small flies known as midges; once trapped, the insects are broken down by an enzyme produced by the plant, allowing it to absorb nutrients from the prey.

Confirmation of a long-standing hypothesis

Darwin speculated more than a century ago that some nonclassic carnivorous plants might capture insects, and this contemporary work provides empirical support for his idea in the case of S. candelabrum. The discovery underscores how subtle adaptations can function as complementary nutrient strategies in nutrient-poor alpine environments.

Broader implications

The study sheds light on the diversity of carnivorous adaptations among flowering plants and highlights the importance of careful observation and experimental follow-up in validating historical hypotheses. By documenting both the adhesive trapping mechanism and the enzymatic digestion, researchers have clarified how this alpine species supplements its nutrient intake in challenging habitats.