Honeybee, Apis mellifera, round dance is influenced by trace components of floral nectar

The round dance and mutual feeding (trophallaxis) enable honeybees to transfer information concerning a food source, including its profitability. For nectar, which consists mainly of sugars, profitability is usually defined by its energetic value. Nectars, however, also contain a wide range of trace components, some of which affect their attractiveness. Honeybees produce honey from nectar. We compared the round dance and trophallaxis behaviours of bees foraging on avocado and citrus honey solutions, as a substitute for nectars. These sources differ in their trace-elements composition, with avocado nectar and honey containing higher concentrations of minerals than citrus nectar and honey. In a second experiment, we compared the behaviour of bees foraging on sucrose solution and sucrose solution enriched with four major mineral components of avocado nectar. Subjects foraging on avocado honey had a significantly lower probability of dancing than those foraging on citrus honey, a rate of direction reversals that was almost one half, a lower total number of reversals, shorter dance duration and longer trophallaxis time. When avocado honey was supplied to bees that previously fed on citrus honey, most of them avoided it, indicating a strong context effect. When foraging on mineral-enriched sugar solution, dance variables tended to be lower compared with sucrose solution without minerals, but differences were smaller than the differences between the honey solutions. These results show that nectar trace components affect the estimation of nectar profitability by bees and consequently recruitment of new foragers to nectar sources.