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Unlike nectar, bees do not ingest pollen whilst foraging on flowers, and so until now it has been unclear whether they are able to assess whether a flower will give good pollen based on its appearance.

However, in a study published at the end of July, University of Exeter researchers used bumblebee foragers, housed under controlled conditions to test a hypothesis that bees learn about flowers during pollen collection. Their results show that bumblebees can individually assess pollen samples and discriminate between them during collection, and suggest that the bees quickly form preferences for a particular type of pollen.

The researchers said their findings indicate that pollen foraging behaviour involves learning and individual decision-making, which may allow bees to quickly learn which flowers provide the most nutritious pollen rewards for rearing their young.

Dr Natalie Hempel de Ibarra, Senior Lecturer in Neuroethology at the University of Exeter, commented, "There is still very little known about how bees decide which flowers to visit for pollen collection. Easily learning floral features based on pollen rewards, without needing any nectar rewards, is a fast and effective way to recognise those flower species which bees have previously experienced to be the best ones."

Dr Elizabeth Nicholls, who contributed to the research at Exeter, sadded, "Bees need to be able to select flowers providing the most nutritious food for rearing their young. Since bumblebees don't eat pollen when foraging, it was unclear if or how they might be able to assess differences in quality. Here we've shown that they are able to detect differences in pollen, even before landing, which means they may be able to tell, just from the colour of the petals, which flowers are worth visiting.

"We already know a lot about how and what bees learn when collecting nectar from flowers, but since bees don't eat pollen when foraging, we were interested to see whether they could still learn which flowers to visit when collecting this resource."