Honeybee odometry and scent guidance.

We report on a striking asymmetry in search behaviour observed in honeybees trained to forage alternately at one of two feeder sites in a narrow tunnel. Bees were trained by periodically switching the position of a sucrose reward between relatively short and long distances in the tunnel. Search behaviour was examined in the training tunnel itself and in a fresh tunnel devoid of scent cues deposited by bees during training. Bees tested in the fresh tunnel exhibited a bias towards the shorter site, while bees tested in the training tunnel searched closer to the longer site. In additional experiments, we manipulated the position of scent cues, relative to the training location, in the testing tunnel. Bees generally searched at the site to which they were trained rather than at the position of the scent. Our data argue strongly against the hypothesis that bees rely exclusively on deposited scent to accurately localise a food source in natural foraging environments. We instead conclude that odometry and scent guidance contribute to honeybee food search in a manner reflecting the significance and relative reliability of sensory information.