How bumblebees manage conflicting information seen on arrival and departure from flowers

Abstract

Bees are flexible and adaptive learners, capable of learning stimuli seen on arrival and at departure from flowers where they have fed. This gives bees the potential to learn all information associated with a feeding event, but it also presents the challenge of managing information that is irrelevant, inconsistent, or conflicting. Here, we examined how presenting bumblebees with conflicting information before and after feeding influenced their learning rate and what they learned. Bees were trained to feeder stations mounted in front of a computer monitor. Visual stimuli were displayed behind each feeder station on the monitor. Positively reinforced stimuli (CS+) marked feeders offering sucrose solution. Negatively reinforced stimuli (CS-) marked feeders offering quinine solution. While alighted at the feeder station the stimuli were not visible to the bee. The “constant stimulus” training group saw the same stimulus throughout. For the “switched stimulus” training group, the CS+ changed to the CS- during feeding. Learning was slower in the “switched stimulus” training group compared to the constant stimulus” group, but the training groups did not differ in their learning performance or the extent to which they generalised their learning. The information conflict in the “switched stimulus” group did not interfere with what had been learned. Differences between the “switched” and “constant stimulus” groups were greater for bees trained on a horizontal CS+ than a vertical CS+ suggesting bees differ in their processing of vertically and horizontally oriented stimuli. We discuss how bumblebees might resolve this type of information conflict so effectively, drawing on the known neurobiology of their visual learning system.

Bumblebee visual learning: simple solutions for complex stimuli

“…Why this may be not clear, but our data are consistent with bees learning the vertical bar as rewarded faster than the horizontal bar as rewarded. This has been seen in other studies (Srinivasan et al 1999, Wang, Tie et al 2014, Wolf et al 2015, Guiraud et al 2023).…”

“…We observed differences in learning between the bees trained with the CS+ containing the vertical single element and the horizontal single element. Ours is not the first to report bees learn visual and horizontal stimuli at different rates (MaBouDi et al 2021, Guiraud et al 2023). Why this may be not clear, but our data are consistent with bees learning the vertical bar as rewarded faster than the horizontal bar as rewarded.…”

“…For the gratings, only bees in the groups where the CS was associated to the horizonal single bar and the 45° gratings (H groups) showed a significant preference for the rewarded orientation over the punished orientation. This can be partly explained by their scanning behaviour when approaching these patterns (MaBouDi et al 2021), but also due to the nature of their visual system (Guiraud et al 2023). All four groups chose bar elements more than grating elements, but this difference was only significant for bees from the group that associated the CS+ with the vertical single bar and the 45° gratings (V groups, Fig.…”