Pollinator power Bees are ‘better’ plant cultivators

Plants pollinated by bumblebees become more fragrant

(University of Zurich)

Pollinators like bees play a much greater role in plant evolution than previously thought, according to a University of Zurich study. It found that after just nine generations, the same plant was larger and smelled sweeter if pollinated by bumblebees rather than flies.

For their experiment, researchers used field mustard – a kind of cabbage species and a close relative of oilseed rape. One group was pollinated solely by bumblebees for nine generations, another by hoverflies and a third by hand.

They found that plants that were pollinated purely by bees had more fragrant flowers with greater UV colour component. Those plants that relied solely on hoverflies to aid reproduction were smaller, considerably less fragrant and self-pollinated much more.

Field mustard: the plant pollinated by bumblebees is larger (left) than the plant pollinated by hoverflies

Field mustard: the plant pollinated by bumblebees is larger (left) than the plant pollinated by hoverflies

(University of Zurich)

“The traditional assumption is that evolution is a slow process,” said Florian Schiestlexternal link, a professor at the university’s Department of Systematic and Evolutionary Botany in a statement.external link  But “a change in the composition of pollinator insects in natural habitats can trigger a rapid evolutionary transformation in plants”.

With pesticides decimating bee populations, the researchers concluded that plants were capable of adapting to other pollinators within a relatively short space of time. However, Schiestl fears that adapting to fewer types of pollinator could reduce the plant population’s genetic variability and make it more susceptible to disease.

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