LEARNT SENSORIMOTOR MAPPINGS IN HONEYBEES - INTERPOLATION AND ITS POSSIBLE RELEVANCE TO NAVIGATION

We investigated the ability of bees to associate a motor parameter wit h a sensory one. Foragers were trained to fly along a prescribed route through a large box which was partitioned into compartments. Access f rom one compartment to the next was through a hole in each partition. In two of the compartments, the back wall was covered with a grating o f black and white stripes. Stripe orientations and the required trajec tories differ-ed in the two compartments so giving bees the opportunit y to learn that one stripe orientation signalled the need to fly leftw ards and the other rightwards. We videotaped the bees' trajectories th rough one of these compartments in tests with the grating on the back wall in one of four possible orientations. Flight trajectories to stri pes in the training orientations were appropriately to the left or to the right implying that bees had linked a given flight direction to a given stripe orientation. With gratings oriented between the training values, flight directions were, under some conditions, intermediate be tween the training directions. This interpolation indicates that the t raining regime had induced a continuous mapping between stripe orienta tion and trajectory direction and thus suggests that trajectory direct ion is a motor parameter which is encoded explicitly within the brain. We describe a simple network that interpolates much like bees and we consider how interpolation may contribute to the ability of bees to na vigate flexibly within a familiar environment.