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STORY 1 OF2..
Honeybees
smell a rat and outsmart flowers
Buzzing pollinators could
be driving flower to produce their sweet
aromas
Bees
can quickly learn which flowers
produce the best nectar by the
way they smell, even when they
smell extremely similar. This
finding, published today in the
journal Proceedings of the Royal
Society B, has helped scientists
to understand how flowers
evolved to smell the way they
do.
Producing nectar is a costly business for plants but helps them attract insects such as bees which can carry out cross pollination a crucial part of plant reproduction. Some plants try to cheat the system by producing low grade nectar, and advertising with attractive smells. By learning which smells lead to the sweetest rewards, honeybees can outsmart potential cheating' flowers which may be touting low quality nectar, say the scientists from Newcastle University behind the research.
'Our research shows that because bees can learn about the signals associated with nectar quality they have the means of avoiding floral cheaters,' preferring instead to visit the floral scents they've learned to associate with profitable rewards,' says biologist Dr Geraldine Wright.
Just as a delicious smells lure customers to a good restaurant, flowers use scent signals, as well as colours and shapes, to remind bees of the treats they have in store. But some plants try to cheat the system, using these same cues to falsely advertise poor quality nectar or even none at all.
Now scientists know that bees can outsmart flowers which might be trying to cheat them out of their dinner, and instead make a beeline for the ones they know will offer the best rewards.
'This is extremely important to plants because it affects whether or not bees visit them and, therefore, whether or not plants sexually reproduce,' says Wright. What's more, bees' ability to learn could be a driving force behind how the smell of flowers evolves.
'It forces flowering plants to be honest about the rewards they advertise and may even select for plants both with scented flowers and with high quality flowers because these plants out-compete others in a floral market place,' she says.
Source: The Royal Society
Technology & Science
Honeybees don't fall for cheap
perfume
Buzzing pollinators could be
driving flower to produce their sweet aromas
By
Jennifer Viegas
Fragrant spring flowers and floral perfumes are possible thanks to the discriminating scent sense of honeybees, suggests a new study that found the buzzing pollinators could be driving flowers to produce their intoxicating aromas.
Scientists were able to train the honeybees to associate two similar odors with different nectar rewards. The results left little doubt over what honeybees like to sip: soda-sweet nectar.
"Bees tend to like sugary solutions that are about equivalent to the concentration of sugar in Coca Cola (around 30 percent sucrose)," lead author Geraldine Wright told Discovery News.
"If the nectar is too sugary, it is too viscous and difficult to drink," added Wright, a lecturer at Newcastle University's School of Biology. "They don't like salty solutions."
With this information in mind, Wright and colleagues Amir Choudhary and Michael Bentley exposed collected worker honeybees to a few different odors based on natural floral compounds. Each odor led to a particular food reward, with one having more sugar and the other containing more salt.
The findings are published in the current Proceedings of the Royal Society B.
The bees quickly learned to distinguish between the two odors, based on their associated rewards. The strength of the bees' bias depended on how delicious, or awful tasting, the food solutions were to them.
"In fact," Wright said, "our research indicates that in addition to becoming biased towards scents associated with good quality rewards, bees can equally become biased away from scents associated with bad outcomes. This would mean that a scent signal could be used by bees to avoid visiting flowers."
For plants that hope to attract honeybees, there may even be a "keeping up with the Joneses" effect, where plants are under pressure to maintain nectar rewards of similar quality to their neighbors, while simultaneously releasing enticing fragrances to draw in desired pollinators.
The big difference between plants and humans linking odors to foods, however, is that the volatile compounds produced by floral tissues aren't necessarily coming from the nectar itself. In contrast, if a person salivates smelling a savory pizza or chocolate dessert, the individual perceives odors given off by the food.
"The dissociation of signal and outcome means that a (flower) odor could potentially become a dishonestly used signal or floral reward," Wright said.
But honeybees are too smart to fall for this cheap perfume with a lousy reward scenario, the study indicates. Since the bees quickly and continuously learn which scents yield the best nectar, "this prevents plants from using floral scent dishonestly."
Good looks without substance don't fool honeybees either.
"Floral scent is a cue heavily relied upon by bees to discriminate among some flowers," Wright explained. "When the floral scent isn't correct, even if the visual aspects of the flower are exactly the same, a bee will not visit it."
She added that humans, like bees, also probably learn to associate particular smells with certain outcomes, such as when a woman detects a man's sweat.
Charles Wysocki, a behavioral neuroscientist at Monell Chemical Senses Center, recently tried, and mostly failed, to prevent women from detecting male sweat by masking the masculine odor with various other fragrances.