Cacti Generate New Species Fast Via Flower Shape Evolution
Get the Health newsletter
Daily health & science — research, biotech, public health, the studies worth knowing. Free.
- University of Reading researchers found that cacti whose flowers change shape most quickly are far more likely to branch into new species, based on flower length data from over 750 cactus species ranging from 2mm to 37cm.
- Lead author Jamie Thompson said flower size made almost no difference to speciation rates, overturning the researchers' own assumption that longer, more specialized flowers would drive new species formation.
- The findings challenge Charles Darwin's orchid-based hypothesis that specialized flower forms are the engine of new plant species, with the effect holding across both recent and deep evolutionary history.
- The cactus family contains roughly 1,850 species that spread across the Americas over the past 20 to 35 million years, making it one of the fastest-expanding plant groups on the planet.
- Nearly a third of all cacti are threatened with extinction, and Thompson argued that evolutionary pace — not any single trait — should be folded into conservation triage to predict which species need the most help.
- The seven-year project produced a shared cactus trait database covering species, habitats, and evolutionary relationships, published in Biology Letters (2026) as a resource for biodiversity and climate-change research.
Why it matters: With nearly a third of cacti threatened with extinction, the study hands conservationists a new triage tool: evolutionary pace, measured by how fast a species' flowers change shape, may predict which lineages can keep up with rapid environmental change and which need intervention. The Reading team's free database gives researchers worldwide the first shared resource to test those predictions at scale across roughly 1,850 species.
