Pollinator efficiency, rather than bee decline, explains a shift to hummingbird pollination in tropical montane forests.
Juárez P, Gerhardt K, Hughes E, Girvin C, Dellith-Moser A
Pollinators
Next time you spot a hummingbird hovering at a tubular red flower in a mountain garden, you're watching millions of years of evolution in action — the flower didn't just attract hummingbirds, it was shaped by them.
Two closely related ginger plants in Costa Rica use different pollinators — one relies on bees, the other on hummingbirds. Researchers moved plants to different elevations and watched who showed up. They discovered hummingbirds win out not because bees go away on mountaintops, but because hummingbirds carry more pollen per flower visit and visit more often at higher elevations.
Key Findings
Hummingbird-pollinated Costus wilsonii had higher overall pollinator effectiveness than the bee-pollinated species despite bees visiting more frequently.
Bee visitation remained consistent across all elevations in the transplant experiment, disproving the 'bee decline on mountains' hypothesis.
Hummingbird visitation increased with elevation for the hummingbird-adapted species, explaining why high-altitude plants evolve toward hummingbird pollination.
chevron_right Technical Summary
Scientists tested why some tropical plants switched from bee to hummingbird pollination as you go higher up a mountain. They found it's not that bees disappear at high elevations — it's that hummingbirds are simply better at transferring pollen per visit, and they become more common at higher elevations.
Abstract Preview
A longstanding but untested hypothesis proposes that reduced bee visitation in tropical montane cloud forests has repeatedly driven the evolution of hummingbird pollination. Here, we test whether r...
open_in_new Read full abstractAbstract copyright held by the original publisher.
Species Mentioned
Was this useful?
Urban Tree Canopy Reduces Heat-Related Mortality by 39% in European Cities
Trees in your local park or street aren't just pretty — they are literally keeping people alive during heatwaves, and planting even a modest number of the ri...
Costus is a genus of herbaceous perennial plants in the family Costaceae, described by Linnaeus in 1753. It is widespread through tropical and subtropical regions of Asia, Africa, and the Americas.