Some plants are effectively drugging the bees with caffeine. It was thought that caffeine was an anti-herbivore response. But it modifies bee brains as well.
In a long-term memory experiment caffeinated bees remembered an odour better than their non-caffeinated sisters. Three times as many bees on caffeine stuck out their tongues for a reward 24 hours after training, compared to their decaffeinated sisters, and twice as many recalling it 72 hours later. Caffeine thus appears to help the bees learn.
Plants are thought likely to benefit because the bees remember where the tasty reward is and come back for more (thus more pollination).
Caffeine modifies how bee brain neurons respond to learning and memory tasks. It appears to result in a stronger reaction of bee-brain cells to sensory input. These stronger reactions in term causes a long-term potentiation, which is a major mechanism resulting in memory formation.
I’m going to keep drinking my coffee…