Honeybees are extraordinary animals, and for years scientists have looked at them for inspiration to develop new technologies from artificial hive mind computers to explosive detectors. Bees have been truly gifted by nature, and we’re only starting to unravel the many abilities these fantastic insects possess. Recently, researchers at Newcastle University have found that bees enjoy a good “cup of java” just like any of us humans, after they found caffeine helps dramatically boost bees’ memory. This leads to a preferential treatment for plants containing caffeine.
There are many plants that contain caffeine, like those in the genuses Coffea and Citrus, a feature typically developed by the plants in order to fend off pestering insects. Fortunately for bees, the caffeine concentration in most of these plants doesn’t harm them, on the contrary.
“Remembering floral traits is difficult for bees to perform at a fast pace as they fly from flower to flower, and we have found that caffeine helps the bee remember where the flowers are,” study leader Geraldine Wright, a neuroethologist at Newcastle University, UK, said in a statement. “Caffeine in nectar is likely to improve the bee’s foraging prowess while providing the plant with a more faithful pollinator,” Wright added.
To test how caffeine affects bees, the researchers measured the concentration in each of the studied plants, including robusta and arabica, as well as Citrus plants like grapefruit, lemons, pomelo and oranges. They found that caffeine was well within the tolerated threshold for bees.
Then, the scientists performed a Pavlovian conditioning experiment. Bees have a feeding mechanism in which they stick out feeding parts out of their mouth when in the vicinity of a sweet nectar. The researchers trained the bees to engage in feeding behavior when sensing a floury scent, and then rewarded them with either sugar or caffeinated sugar.
Even 24 hours later, three times as many bees remembered the scent that was paired with a caffeine reward as the plain sugar and twice, while twice as many bees remembered the flowers’ scent after three days. There’s always the possibility that caffeine might have made bees more responsive to scent, however the researchers ruled out this idea and concluded that cognition is the primarily affected.
“I think it’s the first example of nature manipulating memory in an animal,” neuroscientist Serena Dudek of the National Institutes of Health, who was not involved in the study, told LiveScience. “We all have this impression that caffeine is made to be toxic to animals,” Dudek said, but “it’s surprising that these plants use caffeine not as a toxin but as an advantage in getting bees to remember better.”
To find out how exactly caffeine helped bees remember better, the researchers recorded activity from bees’ Kenyon cells – somewhat homologous to our hippocampal neurons, responsible for creating and storing memories – and found these became more excited in response to caffeine stimuli. Too much caffeine, however, can be toxic to bees and apparently the insects have developed a sort of sensor that allows them to detect high concentrations and stay away.
Findings were reported in the journal Science.
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