Making learning easy: the acquisition of visual information during the orientation flights of social wasps

Abstract

The flights of individual wasps (Vespula) were recorded as they approached a small feeder on the ground that was marked by a black cylinder ca 15 cm away. Two navigational strategies are used in these approaches. Initially, the wasp aims at the cylinder, treating it as a beacon and fixating it with frontal retina. In the last stage of the flight, the wasp assumes a preferred orientation so that the cylinder takes up a constant, more peripheral retinal position as the wasp nears the feeder. Path guidance by image-matching is likely to be limited to this final segment of the return. Wasps could gain the information needed for these distinct navigational strategies during the learning flights that they perform on their initial departures from the feeder. They fly away from the feeder in a series of arcs while turning at a mean angular velocity of 226°/s. The cylinder tends to be viewed with frontal retina during the arcs suggesting that the information required for aiming at the cylinder is acquired then. For image matching, the appearance of the cylinder needs to be learnt when the wasp is in the orientation that it adopts close to the feeder on its return flight. Wasps tend to assume this orientation during learning flights while they face the feeder. Such inspections of the feeder occur at the ends of arcs when a wasp's turning velocity is low.