Darwin proved right about gnat-trapping carnivorous plant
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- Charles Darwin predicted carnivory in two Saxifraga species in 1875, four years after On the Origin of Species, but his own experiments could not prove the plants digested captured insects
- Saxifraga candelabrum specimens from Wufeng Mountain in Yunnan, China, trap small insects — primarily gnats — using sticky secretions on hair-like structures, while letting larger pollinating insects escape
- Mature plants in field surveys carried an average of more than 70 insects each, and lab tests confirmed the secretions contain digestive enzymes that break down prey
- Nitrogen isotope tracing demonstrated that nutrients from digested insects are absorbed into the plant's tissues
- Genetic analysis showed Saxifraga shares carnivory-related genes with a sundew (Drosera spatulata) and a flycatcher bush (Roridula gorgonias), controlling prey attraction, digestion, and nutrient uptake
- Doug Soltis at the University of Florida said the team expects other Saxifraga species and wider family members to be re-examined for carnivory, noting many carry similar sticky hairs
- The study was published in Nature Communications (DOI: 10.1038/s41467-026-75288-y)
Why it matters: Darwin suspected these plants were carnivorous in 1875 but lacked the tools to prove it. The new enzymatic, isotopic, and genetic evidence finally classifies Saxifraga as a true carnivorous genus — and Soltis's team expects this to trigger re-examination of many of the roughly 450 species in the genus and related family members that share the same sticky hairs.
