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

Abstract

Bumblebees rely on diverse sensory information to locate flowers while foraging. The majority of research exploring the relationship between visual and olfactory floral cues is performed at local spatial scales and applicable to understanding floral selection. Floral cue-use during search remains underexplored. This study investigates how the bumblebee Bombus impatiens uses visual versus olfactory information from flowers across behavioral states and spatial scales. At local spatial scales, non-flying animals in an associative learning paradigm will access learned multimodal cues in an elemental fashion - where a single component of the cue is capable of eliciting responses. However, bumblebees flying in a windtunnel shift cue-use strategy depending on the spatiotemporal scale of cue encounter. When both color and odor cues mimic local/within patch spatial scale, bumblebees exhibit a gradient of elemental responses - with highest responses to the complete multimodal color+odor cue, followed by intact color, then intact odor. When cues mimic an intermediate/between patch spatial scale, bumblebees exhibit configural responses to the learned cue - with high responses to only the learned color+odor cue. Thus the underlying physiological state, sensitive to both activity level and spatiotemporal scale of sensory information, is modulating encoding and utilization of multimodal floral cues.