Can't get going without the buzz from caffeine in your morning cup of joe? You may have more in common with honeybees than you might guess! It turns out that bees get a buzz from caffeine too -- delivered by a flower rather than in a steaming mug of coffee, however.
Caffeine is present in the nectar of some flowers, such as coffee (not surprisingly) and citrus. In fact coffee flowers naturally contain about the same concentration of caffeine as a cup of instant coffee! It's thought that one purpose of caffeine and similar bitter compounds in plants is to protect them by acting as a deterrent to feeding by foraging animals.
But caffeine at least seems to serve another purpose as well. The bees that collect the caffeine-laced nectar from flowers get hooked on the buzz. A study done at Newcastle University in England and reported in Science News showed that bees are more likely to remember a flower if its nectar contains caffeine, suggesting that the caffeine strengthens the reward circuitry in the a bee's brain and makes it more likely that the bee will be a return visitor. This is beneficial to the flower since the more often a pollinator visits a particular type of flower, the more likely it is that the flower will get paid a call by an insect carrying pollen from the same type of plant, a requirement for successful pollination.
Says Geraldine Wright, one of the authors of the study, ″This is the first instance to show that something we [humans] use as a drug is also a drug ecologically.″ Just don't let Starbucks know!
To read more about how caffeine's buzz attracts bees to flowers, go to Science News.