Plants in Ecuador and Costa Rica have evolved a remarkable 'bellows' system for blowing pollen onto feeding birds.
Agnes Dellinger and Jürg Schönenberger at the University of Vienna and their colleagues found that the flowers of the tropical genus Axinaea contain stamens with bulbous appendages. When these are grabbed and squeezed in the beaks of passerine birds, a blast of air from the cavity-filled appendages fires a jet of pollen onto the birds' heads and beaks.
The stamens provide a highly sugar-rich food for the birds, rather than the nectar or pollen reward that is more usually offered by flowers. The researchers did not observe insects foraging on the Axinaea flowers (pictured), but multiple bird species were seen feeding on them, suggesting that these stamens are a novel pollinator-activated pollen delivery system.
Curr. Biol. http://doi.org/thv (2014)