Interference, response competition, and spatial memory in honeybees, Apis mellifera

Honeybees use a sequence of memory-based servomechanisms to reach a target location. Different memories need to be retrieved, each at the right time. It is thought that appropriate contextual cues guide memory retrieval (context-memory link). One corollary is that learning a second task in the same context should interfere retroactively with memory for the first learned task. This is because the context will prime both memories, only one of which is appropriate. Free flying bees flew to a table in a lab or outdoors for reward (sugar water) whose location was specified by a landmark, e.g. always to the north of the landmark. The landmark-reward array was moved from trial to trial. This ensured that the landmark was the only valid predictor of the exact location of reward. They then learned a second task at the same site, and were tested again on the first task. Performance on re-test was worse if, and only if, the second task demanded a conflicting spatial response (searching in a different direction from another landmark). Learning a colour discrimination task or a second spatial task with a different landmark but with the same target direction from the landmark did not disrupt performance on the first learned task. Results implicate response competition as the likely locus of retroactive interference.