Biologists and bee experts from universities in the United Kingdom and the United States reported a memory improvement in bees that were exposed to caffeine naturally and synthetically in the March 7, 2013, issue of the journal Science.
The researchers found that long and short term memory for the positioning of flowers improved in honey bees that sipped nectar from flowers that contained caffeine. Coffee plant flowers and some citrus plant flowers contain low levels of caffeine. High levels of caffeine repel bees.
The researchers exposed a group of test bees to a sugar solution that contained caffeine and to a non caffeinated sugar solution. The caffeine levels were selected that came within the range of the caffeine levels that bees would naturally be exposed to in the wild around coffee or citrus flowers.
The bees that drank the caffeine laced sugar water demonstrated a scent memory for 24 hours. Twenty-four hours is three times the normal length for bee memory for flower positions. Three times as many bees remembered the caffeine laced flowers position for three days.
The caffeine exposed bees also demonstrated what could be interpreted as an addictive behavior associated with caffeine.
The caffeine triggered changes in the membrane potential of neurons involved in olfactory learning and memory in the exposed bees. Similar reactions have been documented in humans.
The research may assist in promoting higher rates of pollination due to better memory in declining bee populations.