Follow the pollen

An apis mellifera showing safe sites with fluorescent sunflower pollen.
An Apis mellifera showing safe sites with fluorescent sunflower pollen.
Credit: Petra Wester

When a honeybee or bumblebee visits a flower, it drinks nectar and gets covered in pollen.

The bee then grooms itself, cleaning off the pollen and storing it away in special cavities known as pollen baskets to take back to the hive, where it will be mixed with honey or nectar to form “bee bread” that is fed to larvae.

But the bees can’t keep all the pollen for themselves. The plants rely on them to carry pollen off to other flowers. Without this pollination, there will be no future generations of plants for future generations of bees to feed on.

Apiarists have noticed in the past that some bees leave some pollen behind on their bodies when grooming. This pollen most commonly remains in certain areas, known as “safe sites”, around the waist, thorax and abdomen.

To test whether these safe sites enabled pollen transfer, scientists from Heinrich-Heine-University, Germany, looked at the points of contact foraging bees have with anthers – which produce pollen – and stigma – which receive it for fertilisation.

By letting bees feed from flowers whose anthers and stigma had been coated with fluorescent dyes, the researchers could see where these parts of the flower touched the bees. They found that anthers and stigma both touched the safe sites most commonly, thus enabling the transfer of pollen.

The research is published in PLOS ONE.

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