Honeybee dances communicate distances measured by optic flow

In honeybees, employed foragers recruit unemployed hive mates to food sourc es by dances from which a human observer can read the distance and directio n of the food source(1). When foragers collect food in a short, narrow tunn el, they dance as if the food source were much farther away. Dancers gauge distance by retinal image flow on the way to their destination. Their visua lly driven odometer misreads distance because the close tunnel walls increa se optic flow(2). We examined how hive mates interpret these dances. Here w e show that recruited bees search outside in the direction of the tunnel at exaggerated distances and not inside the tunnel where the foragers come fr om. Thus, dances must convey information about the direction of the food so urce and the total amount of image motion en route to the food source, but they do not convey information about absolute distances. We also found that perceived distances on various outdoor routes from the same hive could be considerably different. Navigational errors are avoided as recruits and dan cers tend to fly in the same direction. Reported racial differences in hone ybee dances(1) could have arisen merely from differences in the environment s in which these bees flew.