Caffeine-infused nectar tricks honeybees into changing their foraging behaviour in ways that may benefit the plant.

Many plants produce the bitter-tasting caffeine to deter herbivores, but also rely on bees to spread their pollen for reproduction. To look at caffeine's effect on pollinators, Margaret Couvillon and her colleagues at the University of Sussex near Brighton, UK, monitored honeybees feeding from a sugar solution. They then compared the bees' behaviour to those feeding on the same solution but with caffeine added at a concentration found in nectar. The caffeine-fuelled bees revisited the feeders more frequently than did the control bees, and they at least tripled the number of waggle dances they performed to recruit bees from the hive.

Because caffeine disguises a reduced sugar concentration, the nectar the bees take back to the hive might be sub-standard. That could mean that the colony would produce less honey, the authors predict.

Curr. Biol. http://dx.doi.org/10.1016/j.cub.2015.08.052 (2015)