Identification of carnivory in the flowering plant Saxifraga via multidisciplinary evidence

Abstract

Abstract The transformation from prey to predator is a striking adaptive innovation shared by all carnivorous plants, which capture and digest diverse animal prey for nutrients (nitrogen, N). Here, we report carnivory in the alpine flowering plant Saxifraga candelabrum (Saxifragaceae; Saxifragales). Field experiments and herbarium surveys reveal that this plant actively attracts and captures insect prey via glandular hairs. Enzymatic analyses further confirm the ability of plants to digest prey, and isotope labelling experiments using ¹⁵N-labelled insects demonstrate the transfer of nitrogen from prey to plant tissues, thus verifying the presence of carnivory. Genomic comparisons reveal a significant genome-wide convergence in genes related to carnivory (e.g., leaf morphogenesis, digestion and nutrition) across six independent origins of carnivory in diverse flowering plant lineages. Our findings provide definitive evidence of carnivory in Saxifraga , addressing Charles Darwin’s long-standing hypothesis that some Saxifraga species may be capable of carnivory, and further suggest that carnivory may be more widespread among angiosperms than previously recognized.