Incentive contrast in honey bees.

Bees trained to come to the laboratory for a 20% sucrose solution accept it readily, but bees trained with a 40% sucrose solution and tested with the 20% solution show a pattern of interrupted feeding that may last for several minutes. Bees trained with 20% and tested with 40% sucrose are undisturbed. When the animals are offered two samples of the 20% solution simultaneously, they drink to repletion from whichever they first taste on each visit, but if both a 20% and a 40% drop are offered the 20% solution is rejected after a single experience of the 40% solution. Although these results are analogous in many respects to incentive contrast effects found in mammals, they can be understood in sensory terms and do not require the assumption of learning about reward.