Flowers have scent runaways to guide bees quickly to the nectar, a study found.
Like the colours and stripes on many petals, they also have scent patterns to guide bees to the centre of the flower.
The petals are covered in different fragrances which smell differently from the edge and the centre.
These patterns combine with the visual signals, scientists from the University of Bristol and Queen Mary University of London said.
They were able to show this scent patterning might be a signal to a bee by creating artificial flowers that have identical scents arranged in different patterns.
Professor Lars Chittka, from Queen Mary’s School of Biological and Chemical Sciences, said: “We already knew that bees were clever, but we were really surprised by the fact that bees could learn invisible patterns on flowers – patterns that were just made of scent.
“The scent glands on our flowers were either arranged in a circle or a cross, and bees had to figure out these patterns by using their feelers.
“But the most exciting finding was that, if these patterns are suddenly made visible by the experimenter, bees can instantly recognise the image that formerly was just an ephemeral pattern of volatiles in the air.”
Lead author Research Associate Dr Dave Lawson, from the University of Bristol’s School of Biological Sciences, these patterns can often be seen simply by looking at flowers through a microscope.
He said: “If you look at a flower with a microscope, you can often see that the cells that produce the flower’s scent are arranged in patterns.
“By creating artificial flowers that have identical scents arranged in different patterns, we are able to show that this patterning might be a signal to a bee.
“For a flower, it’s not just smelling nice that’s important, but also where you put the scent in the first place.”
The study also revealed bumblebees are able to switch between their senses, identifying scent patterns with their sense of smell and then looking for unscented flowers that had visual spots arranged in similar visible patterns.
Dr Lawson added: “This is the equivalent of a human putting her hand in a bag to feel the shape of a novel object which she can’t see, and then picking out a picture of that object.
“Being able to mentally switch between different senses is something we take for granted, but it’s exciting that a small animal like a bee is also able to do something this abstract.”
The exciting research showed not only could bees learn invisible patterns just made of scent but they were immediately able to recognise an equivalent visible pattern made by scientists as part of the experiment.
Scent glands on the scientists’ flowers were either arranged in a circle or a cross and bees had to figure out these patterns by using their feelings.
Senior author Senior Lecturer Dr Sean Rands, also from Bristol, said: “Flowers often advertise to their pollinators in lots of different ways at once, using a mixture of colour, shape, texture, and enticing smells.
“If bees can learn patterns using one sense – smell – and then transfer this to a different sense – vision – it makes sense that flowers advertise in lots of ways at the same time.
“Learning one signal will mean that the bee is primed to respond positively to different signals that they have never encountered.
“Advertising agencies would be very excited if the same thing happened in humans.”
Around 75 per cent of all food grown globally relies on flowers being pollinated by animals such as bees.
The new study was published in the journal Proceedings of the Royal Society B.
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