Same/different discrimination by bumblebee colonies

Bumblebees were exposed to a discrimination procedure in which reinforcement was contingent on choice of one of two spatial locations. The correct choice depended on whether a stimulus display contained two identical stimuli or two different stimuli. Some bees were trained with color stimuli and tested with line grating stimuli and others with the opposite arrangement. Four colonies of bumblebees produced more correct than incorrect choices to both identical and different stimuli during the transfer phase. This pattern of results is a signature of choices under control of an identity (same/different) concept. The results therefore indicate the existence of an identity concept in bumblebees.