Ants have tiny brains but a remarkable ability to travel unerringly to food sites and back to the nest without losing their way. Two researchers at the Sussex Centre for Neuroscience believe they can now explain this navigational skill. The insects take a series of visual "snapshots", first at the site of a food supply and then several times on the way back to the nest, Drs SPD Judd and TS Collett write in the current issue of Nature.
The ants orientate themselves in relation to the objects in the stored mental image. If a given object is smaller than that stored in the memorised snapshot the ant moves towards it, or back if the object is too large. The researchers trained wood ants to find food behind a specific landmark and videotaped them as they made their return to the nest. They turning periodically to make "inspection runs" back towards the food to capture the view. The snapshots allowed the ants to retrace their way without fail back to the food source. Bees seem to adopt a similar strategy given their "turn back and look" flight-paths as they leave a food source.