Active sensing movements by antennae enhance neural processing and plasticity for odour processing in the CNS in the honey bee Apis mellifera

Animals frequently move their sensory organs in response to dynamic environmental stimuli, a behavior called active sensing. Recent research indicates that insects adjust their antennal movements based on the temporal structure and salience of olfactory signals, suggesting that antennae play a role in active sensing. However, the impact of these movements on central olfactory processing is not well understood.

To investigate this, researchers trained honey bee foragers using a proboscis extension response (PER) protocol, pairing one odor with sucrose and another with salt water. This training resulted in distinct antennal movements towards the two odors. Bees were then tested with varying concentrations of both odors, with antennae either fixed or allowed to move freely during both training and testing, while recording their responses from the antennae and antennal lobes.

The peripheral responses to odors were not affected by whether the antennae were fixed or free. However, neurons and local interneurons in the antennal lobes showed learning-related increases in response to the odor paired with sucrose, consistent with prior findings. These increases were more pronounced in bees with freely moving antennae.

Moreover, neural responses were more variable, especially at lower odor concentrations, when the antennae could move, indicating that response variability might contribute to plasticity. These findings support the idea that active antennal movements influence the central processing of odor representations. Future research comparing restrained bees with those allowed to walk freely will help determine the natural behavioral contexts in which antennal movements enhance olfactory sensing.