Bee reverse-learning behavior and intra-colony differences: Simulations based on behavioral experiments reveal benefits of diversity

Foraging bees use color cues to help identify rewarding from unrewarding flowers. As environmental conditions change, bees may require behavioral flexibility to reverse their learnt preferences. Learning to discriminate perceptually similar colors takes bees a long time, and thus potentially poses a difficult task to reverse-learn. We trained free-flying honeybees to learn a fine color discrimination task that could only be resolved (with about 70% accuracy) following extended differential conditioning. The bees were then tested for their ability to reverse-learn this visual problem. Subsequent analyses potentially identified individual behavioral differences that could be broadly classified as: 'Deliberative-decisive' bees that could, after several flower visits, decisively make a large change to learnt preferences; 'Fickle-circumspect' bees that changed their preferences by a small amount every time they received a reward, or failed to receive one, on a particular color; and 'Stay' bees that did not change from their initially learnt preference. To understand the ecological implications of the observed behavioral diversity, agent-based computer simulations were conducted by systematically varying parameters describing flower reward switch oscillation frequency, flower handling time, and fraction of defective 'target' stimuli that contained no reward. These simulations revealed that when the frequency of reward reversals is high, Fickle-circumspect bees are more efficient at nectar collection, but as reward reversal frequency decreases, the performance of Deliberative-decisive bees becomes most efficient. As the reversal frequency continues to fall, Fickle-circumspect and Deliberative-decisive strategies approach one another in efficiency. In no tested condition did Stay bees outperform the other groups. These findings indicate there is a fitness benefit for honeybee colonies containing individuals exhibiting different strategies for managing changing resource conditions. (C) 2014 Elsevier B.V. All rights reserved.