Antenna movements as a function of odorants’ biological value in honeybees (Apis mellifera L.)

Abstract

In honeybees, the antennae are highly mobile sensory organs that express scanning movements in various behavioral contexts and toward many stimuli, especially odorants. The rules underlying these movements are still unclear. Using a motion-capture system, we analyzed bees’ antennal responses to a panel of pheromonal and other biologically relevant odorants. We observed clear differences in bees’ antennal responses, with opposite movements to stimuli related to opposite contexts: slow backward movements were expressed in response to alarm pheromones, while fast forward movements were elicited by food related cues as well as brood and queen related pheromones. These responses are reproducible, as a similar pattern of odor-specific responses was observed in bees from different colonies, on different years. We then tested whether odorants’ attractiveness for bees, measured using an original olfactory orientation setup, may predict antenna movements. This simple measure of odorants’ valence did however not correlate with either antennal position or velocity measures, showing that more complex rules than simple hedonics underlie bees’ antennal responses to odorants. Lastly, we show that newly-emerged bees express only limited antennal responses compared to older bees, suggesting that a significant part of the observed responses are acquired during bees’ behavioral development.

Antennal movements can be used as behavioral readout of odor valence in honey bees

“…This result seems to contradict the study by Cholé et al, in which no change in antennal orientation was found in response to aversive conditioned odors ( Cholé et al, 2015 ). However, recently, Cholé et al have deepened their former study extending their analysis to different odors, reporting that aversive pheromones (including 2-heptanone) elicit backward movements, in agreement with our present work ( Cholé et al 2022 ). Although it might be inaccurate to differentiate innate from learned behaviors ( Gorostiza, 2018 , Mameli and Bateson, 2006 ), it should be noted that 2-heptanone is an odor with a strong innate relevance in the wild and, therefore, is possible that honey bees have been previously exposed to it before their capture.…”

Active smelling in the American cockroach

“…Our first aim was to investigate how antennal movement participates in spatial sampling. It has recently been shown that honeybees orient their antennae towards appetitive odour sources and away from aversive ones (Cholé et al 2022;Gascue et al 2022). Moreover, the analysis demonstrated a general trend of positive correlation between the time the antennae spent focused on an odour target and its valence (Gascue et al 2022).…”