Velcro-like cells on petals help bees stick to flowers

Washington, May 15 (ANI): Scientists at Cambridge University have found that bees make use of small cone-shaped cells on flower petals, which act like 'velcro' on their feet, to stick to flowers and collect nectar.

In a new study, the scientists have shown that bumblebees can recognise the texture of petal surfaces by touch alone, and they prefer landing on petals with conical cells that make it easier to grip, rather than on flat, smooth surfaces.

Having extra grip enables them to extract nectar from the flower more efficiently.

In the natural world, bees can take visual or olfactory cues without needing to land on the flower itself, and thus their ability to identify conical-celled surfaces by touch could be of limited use in terms of flower recognition.

Led by Beverley Glover, the researchers wondered whether the conical cells could play a different role by providing better grip on an otherwise slippery plant surface, and thus make nectar collection easier for the bees.

The researchers tested the above trait by using artificial flowers cast from epoxy resin, half with conical cells and half with flat surfaces.

It was found that when the casts were horizontal, the bees showed no preference and visited each type roughly half the time. But once the angle of the cast increased, it also boosted the bees' preference for the conical cells.

When the casts were vertical, the bees visited the conical-celled ones over 60 percent of the time.

The researchers could visualise why the bees preferred conical cells by using high-speed video photography.

They saw that when bees attempted to land on the flat-celled epoxy petals they would struggle for grip, but on the conical-celled casts the bees could always find grip, stop beating their wings and feed on the flower.

Experimenting in the real world, the researchers used snapdragon plants, which have conical petal cells, and mutant snapdragons, which lack such cells. They found that when the flowers were vertical and required complex handling the bees learnt to recognise the conical-celled flowers and landed on them 74 percent of the time.

"For bees to maintain their balance and hold onto a flower is no easy task, especially in windy or wet conditions. It's great to see that evolution has come up with the simple solution of equipping flowers with a Velcro-like surface that bees can get a grip on," said Glover.

The study has been published online in Current Biology. (ANI)