Flower attracts pollinating flies by mimicking smell of attacked bee

SALZBURG, Austria, Oct. 6 (UPI) -- When a honeybee succumbs to a spider, it releases a scent revealing its distress. Flies know the smell well. To them, the smell works like a dinner bell. The kleptoparasites track the smell to the defeated bee and gather to steal a meal from the triumphant spider.

But the smell doesn't always lead kleptoparasitic flies to a dying bee. It leads them to the flowers of an ornamental plant native to southern Africa called the parachute plant -- also fountain flower and umbrella plant. Its scientific name is Ceropegia sandersonii, and as a new study reveals, its flowers mimic the smell of a distressed bee.

Upon tracking the scent to its dead end, duped flies become momentarily trapped in the umbrella plant's flower, picking up pollen as it tries to escape. The flies become unwilling pollinators.

"This study describes a new example of how a plant can achieve pollination through chemical mimicry of the food sources of adult carnivorous animals," scientists wrote in their new paper, published this week in the journal Current Biology.

"We show that trap flowers of this plant mimic alarm substances of western honeybees to lure food-stealing freeloader flies as pollinators," confirmed Stefan Dötterl, a researcher at the University of Salzburg in Austria.

Very few plants come by their pollinators through deceit. A handful of species pretend to host pollen or nectar, and a few front as an ideal place to lay eggs. But scientists believe this is one of the first flowers found to mimic the smell of a pollinator's preferred dinner.