Active Sensing in Bees Through Antennal Movements Is Independent of Odor Molecule.

This article focuses on characterizing the three-dimensional antennal movement patterns of bumblebees (Bombus terrestris) in response to olfactory stimuli to understand their active olfactory sampling strategy. Using high-speed video tracking and the neural network DeepLabCut, the study found that bumblebees exhibit a stereotyped antennal response composed of a low-frequency, large-amplitude oscillation triggered by odor presence and a constant high-frequency, small-amplitude oscillation. These antennal movements, which occur simultaneously on both antennae and are largely independent of the chemical properties (diffusivity or vapor pressure) of the odorants tested, increase the volume of air sampled compared to a static antenna. The findings suggest that bumblebees employ an active sensing behavior by deploying and oscillating their antennae to enhance odor detection, although the antennal motion does not appear to be specifically modulated by the molecular characteristics of the odor stimuli.