Cold vs. CO₂: anaesthetic effects on insect antennal functionality.

Anaesthesia methods play a crucial role in ensuring the integrity of the animal during experimental studies. This study investigates the impact of two anaesthesia methods, CO₂ and cold treatment, on an insect antennal response to synthetic alarm pheromone compounds. Adult worker hornets were anesthetised, and their antennae excised and tested using an electroantennography set-up with controlled stimulation of alarm pheromone components. Results showed that CO₂-anesthetised hornets exhibited robust antennal responses, while cold-anesthetised individuals displayed none. This result suggests that freezing may impair the functionality of olfactory receptors. In contrast, CO₂ anaesthesia preserves receptor integrity, offering reliable and interpretable results. This study highlights the importance of selecting appropriate anaesthesia techniques to avoid artefacts in insect sensory physiology research and underscores the ecological relevance of studying Vespa velutina nigrithorax alarm signalling.