Orchid's Deception Lures Pollinators

Orchids are lovely, but they’re also devious. Last year, researchers reported that European orchids emit a scent similar to that of female bees to attract male bees to pollinate the flowers (C&EN, June 2, 2008, page 15). Now, researchers in Germany and China have found that Dendrobium sinense, an orchid found on the Chinese island of Hai­nan, lures pollinators with a more aggressive ruse (Curr. Biol., DOI: 10.1016/j.cub.2009.06.067). Hornets are tricked into pollinating the Chinese orchid flowers, according to Manfred Ayasse of Germany’s University of Ulm and colleagues. The researchers discovered that the plants attract hornets by producing (Z)-11-eicosen-1-ol, which hasn’t previously been detected in flowers. This compound is a major component of a pheromone released by honeybees, which serve as prey for the hornets. Hornets attracted by the orchid’s scent pounce on the blossoms, much as they would on honeybees, and in so doing aid in the flowers’ pollination.