Orchids lure male bees by posing as irresistibly scented exotic females

May 27th, 2008 - 5:50 pm ICT by admin  

London , May 27 (ANI): Orchids use their irresistible scent to lure male bees for sex and end up benefiting themselves in their own reproduction, a new study has found.

Orchids sexually deceive male insects by posing as irresistibly scented exotic females, and exploit the males drive to copulate for their own reproduction. Males slip on the flowers mistaking them for female insects, and such fruitless mating attempts by the males would pollinate the orchid.

In fact, some of the orchid flowers seem so exciting to males that they even ejaculate on the flower. And its not the visual beauty of the flowers, but their ability to imitate the female sex pheromone cocktail, which drives the males crazy.

A new trick in the orchids’ repertoire of sexual lures has now been discovered by Nicolas Vereecken and Florian Schiestl at the University of Zurich in Switzerland after they studied geographic variation in pheromone mixes between 15 different populations of the bee Colletes cunicularius and the orchid that mimics it, Ophrys exaltata.

The researchers surprisingly discovered that the flowers consistently smelled slightly different than the female bees in any given population, and this led the scientists to speculate that this different smell is what attracts the males towards orchids.

They said that inbreeding in bees population is a problem as they prefer a quiet life and do not travel much. And in this scenario a stranger may be a welcome opportunity to stir up the gene pool for a bit more variety.

They highlighted that male bees have the hots for exotic perfume, and when given a choice, they disregarded a dummy infused with the pheromone cocktail produced by the girl bee next door to another one with the bouquet of a female from another population. The males visited the scent that was new to them 50 percent more often.

But in case of orchid scent, having greater differences in the pheromone mix, the rate of males thronging the flower was five times as often as that of a local female. Also, manipulating the natural perfume blend of the bees to mimic that of the orchids also nearly doubled the bees’ attractiveness to males.

The same trend was also seen in other species, such as mice, wherein rare females are popular even when inbreeding is common.

“When outbreeding is desirable, it makes sense for males to look for females with exotic scent. But in this case, what they find instead is the orchid,” New Scientist quoted chemical ecologist Manfred Ayasse at the University of Ulm in Germany , as saying. (ANI)

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