CAN HONEY-BEES COUNT LANDMARKS

Honey bees, Apis mellifera, were trained along a row of four identical landmarks (tetrahedral tents 3.46 m high) which were equally spaced in a set-up 300 m long, the feeder being placed between the third and fourth landmarks. In the tests, the number of tents between hive and feeder was altered. Even though many bees continued to search for food at the correct distance, the distance estimation of the bees as a group depended notably on the number of landmarks. If they encountered more landmarks on their way from the hive to the feeder than they had during training, significantly more bees landed at a shorter distance than during control tests with the training landmark set-up. If they encountered fewer landmarks, they flew significantly further. This behaviour meets the basic criteria in most definitions of true counting. Since, however, a transfer of the counting performance on different objects is unlikely to occur, the observed behaviour should be referred to as protocounting (Davis and Perusse 1988, Behav. Brain Sci, 114, 561-615). Landmark (proto-) counting is considered here a special application of a sequential memory for landmarks.