Approach Direction Prior to Landing Explains Patterns of Colour Learning in Bees

Abstract

Gaze direction is closely coupled with body movement in insects and other animals. If movement patterns interfere with the acquisition of visual information, insects can actively adjust them to seek relevant cues. Alternatively, where multiple visual cues are available, an insect’s movements may influence how it perceives a scene. We show that the way a foraging bumblebee approaches a floral pattern could determine what it learns about the pattern. When trained to vertical bicoloured patterns, bumblebees consistently approached from below centre in order to land in the centre of the target where the reward was located. In subsequent tests, the bees preferred the colour of the lower half of the pattern that they predominantly faced during the approach and landing sequence. A predicted change of learning outcomes occurred when the contrast line was moved up or down off-centre: learned preferences again reflected relative frontal exposure to each colour during the approach, independent of the overall ratio of colours. This mechanism may underpin learning strategies in both simple and complex visual discriminations, highlighting that morphology and action patterns determines how animals solve sensory learning tasks. The deterministic effect of movement on visual learning may have substantially influenced the evolution of floral signals, particularly where plants depend on fine-scaled movements of pollinators on flowers.

The role of colour patterns for the recognition of flowers by bees

“…We also aim to understand how flower patterns are learned and recalled through chromatic cues. Our previous findings in discrimination experiments hint at the possibility that bees do not always memorize every aspect of the pattern of a flower that they visit [18,19]. In the present study, we show that both chromatic and spatial pattern cues influence how bees choose between learned and novel patterns and colours in discrimination and recognition tests.…”

Behavioral state influences encoding mechanisms of color and odor integration in a model insect, the bumblebee Bombus impatiens

“…As reviewed by Leonard and Masek [21], the results of multimodal experiments can be shaped by the salience of chosen stimuli. While existing literature supports that bumblebees can learn all of the stimulus values used in these experiments [31,32,39,40], our results indicate that in our FMPER experimental context, yellow and lily of the valley were more appetitive than their counterparts (blue and juniper berry) (figures 1,2). The FMPER experiments, while excellent for probing cognitive capability, are far from a free foraging environment; thus direct translation of this work into field preferences is premature.…”

Tracking the flight and landing behaviour of western flower thrips in response to single and two-colour cues

“…In addition, distance-dependent interaction effects show that final landing strategies may be controlled differently compared to approach flights. For bees, approaching flights from within 5–10 cm towards single- and two-colour blue/yellow stimuli are usually from below the target when the stimulus is arranged in the vertical plane 41 . Such a strategy in approach flights can lead insects to land in specific locations of the target, such as the LED lamp used here.…”

“…Moreover, for UV-A treatments we added red light for tracking purposes, which effectively increased the overall radiance of the stimulus, although the controls here showed that it had little or no influence on our main findings. On the other hand, colour contrast or a visual edge between two colours could aid thrips to differentiate visual cues more easily and induce them to land near boundaries of visual targets, as shown with other insects 41 , 44 . In our results, we found that for yellow and green, the landing sites were concentrated around the edge of the LED near the light contrast border between the LED and the black lamp frame.…”