Duration discrimination in the bumblebee Bombus terrestris

Abstract

The ability to process temporal information is crucial for animal activities like foraging, mating, and predator avoidance. While circadian rhythms have been extensively studied, there is limited knowledge regarding how insects process durations in the range of seconds and sub-seconds. This study aimed to assess bumblebees (Bombus terrestris) ability to differentiate the durations of flashing lights, and use this information in a free-foraging task. Bees were trained to associate either the long or short-duration stimulus with a sugar reward versus an unpalatable solution until reaching a criterion, and then tested without sucrose solution with the same stimuli. In Experiment 1, we tested the ability to discriminate between a long stimulus (2.5 or 5 seconds) vs a short stimulus (0.5 or 1 second). The bees learned to discriminate between the two stimuli. To check whether bees solve the task without using the absolute difference in proximal stimulation as a cue, we ran a second experiment. In Experiment 2, the flashing stimuli were presented for the same total amount of time in a cycle. Bees could discriminate between durations even when the overall amount of stimulation in each presentation cycle was the same. This shows general learning abilities in bumblebees, that can discriminate seconds/subseconds intervals in visual flashing stimuli. This reveals an insects ability to use non-naturalistic stimuli and temporal cues in free foraging.