Duration discrimination in the bumblebee Bombus terrestris

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. We aimed to assess bumblebees' (Bombus terrestris) ability to differentiate the durations of flashing lights 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 s) versus a short stimulus (0.5 or 1 s). The bees learned to discriminate between the two stimuli. To check whether bees solved 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 when the amount of stimulation in each presentation cycle was the same. This shows general learning abilities in bumblebees, that can discriminate second/sub-second intervals in visual flashing stimuli.