Acquisition of visual spatial memory: Orientation and reorientation flights in the honey bee

Honey bees have long served as a model organism for investigating insect navigation. Bees primarily use learned visual features of the environment to guide their movement between the nest and foraging sites. Although much is known about the spatial information encoded in memory by experienced bees, the development of large-scale spatial memory in naive bees is not clearly understood. Past studies suggest that leaming occurs during orientation flights taken prior to the start of foraging. I studied what bees learn during their initial experience in a new landscape by examining the homing of bees displaced after a single orientation flight lasting only 5-10 minutes. Homing ability was assessed using vanishing bearings and homing speed. At release sites with a view of the landmarks immediately surrounding the hive, "first flight" bees, tested after their very first orientation flight, had faster homing rates than "reorienting foragers" which had previous experience in a different site prior to their orientation flight in the test landscape. First flight bees also had faster homing rates from these sites than did "resident" bees with full experience in the test landscape. At distant sites, resident bees returned to the hive more rapidly than reorienting or first flight bees, but in some cases, the reorienting bees were as successful as resident bees.; Vanishing bearings showed that displaced bees headed directly toward home from release sites up to 200-500 m away. Because systematic or random search strategies would have resulted in vanishing bearings uncorrelated with the direction of home, I concluded that homeward-oriented bees must have obtained landmark information during the orientation flight. Thus, the orientation flight must allow bees to learn landscape features that they can see at sites up to 500 m from the nest.; Reorienting bees could fly homeward from a site that offered no direct view landmarks near the nest. This suggests that during their single orientation flight, they had formed a simple route map connecting these visually isolated parts of the terrain. First flight bees were randomly oriented at this release site. Either their orientation flights had covered a less extensive area or their lack of previous flight experience prevented them from learning the route connecting this site to the nest.; A separate series of experiments revealed that visual complexity of landscape features had no influence on the duration of orientation flights. Reorienting bees, however, completed longer orientation flights than first-flight bees. This may explain the inability of first-flight bees to form route maps during the orientation flight.; These experiments show that bees learn about landmarks very rapidly despite their brief exposure to the terrain during the orientation flight, and have provided the first insights into what information is learned by bees with different degrees of experience.