Blue colour preference in honeybees distracts visual attention for learning closed shapes

Abstract

Spatial vision is an important cue for how honeybees (Apis mellifera) find flowers, and previous work has suggested that spatial learning in free-flying bees is exclusively mediated by achromatic input to the green photoreceptor channel. However, some data suggested that bees may be able to use alternative channels for shape processing, and recent work shows conditioning type and training length can significantly influence bee learning and cue use. We thus tested the honeybees' ability to discriminate between two closed shapes considering either absolute or differential conditioning, and using eight stimuli differing in their spectral characteristics. Consistent with previous work, green contrast enabled reliable shape learning for both types of conditioning, but surprisingly, we found that bees trained with appetitive-aversive differential conditioning could additionally use colour and/or UV contrast to enable shape discrimination. Interestingly, we found that a high blue contrast initially interferes with bee shape learning, probably due to the bees innate preference for blue colours, but with increasing experience bees can learn a variety of spectral and/or colour cues to facilitate spatial learning. Thus, the relationship between bee pollinators and the spatial and spectral cues that they use to find rewarding flowers appears to be a more rich visual environment than previously thought.

The answer is blowing in the wind: free flying honeybees can integrate visual and mechano-sensory inputs for making complex foraging decisions

“…4B,C). This is consistent with recent findings that colour is a more hierarchically represented cue in some spatial shape-processing tasks (Morawetz et al, 2013).…”

“…This suggests that neither colour preferences (Morawetz et al, 2013) nor acquired associations during the experiments caused a colour bias that influenced the findings. This result also confirmed that the bees required the presence of wind as a type of occasion-setting cue in order to make accurate colour choices.…”

Getting to the start line: how bumblebees and honeybees are visually guided towards their first floral contact

“…Several recent studies have investigated the fate of the preferences that guide bees to their first floral contact: How easily are they forgotten (Milet-Pinheiro et al, 2012)? Are they distracting (Morawetz et al, 2013)? Can they be associated with consequences such as rewards or punishers (Pohl et al, 2008)?…”

Parallel inputs to memory in bee colour vision*

“…9a) must be poorer as less green contrast is avail able when their training colour is changed from yellow towards blue. Bees trained to distinguish a square and a diamond of various colours, with no tests of what they had actually learned, indeed scored highest when yellow and lowest when blue [19] but it was an error to conclude that they distinguished shape.…”

“…Bees illustrate very well the problems of trying or evolving to see any thing or shape [19]. At the receptors, the panorama is divided, and captured by every receptor sepa rately so the image has to be reassembled.…”