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

Area of Science:

• Insect physiology
• Chemical ecology
• Neuroethology

Background:

• Anesthesia is essential for animal research, but methods can impact physiological responses.
• Insect sensory systems, particularly olfaction, are vital for survival and communication.

Purpose of the Study:

• To evaluate the effects of two anesthesia methods (CO₂ and cold) on insect antennal responses.
• To determine the optimal anesthesia technique for electroantennography studies in hornets.

Main Methods:

• Adult worker hornets (Vespa velutina nigrithorax) were subjected to either CO₂ or cold anesthesia.
• Excised antennae were tested using electroantennography (EAG) with synthetic alarm pheromone stimulation.

Main Results:

• CO₂-anesthetized hornets showed significant antennal responses to alarm pheromones.
• Cold-anesthetized hornets exhibited no antennal response, indicating olfactory receptor impairment.
• CO₂ anesthesia maintained olfactory receptor integrity.

Conclusions:

• CO₂ anesthesia is a suitable method for studying insect olfactory responses, preserving receptor function.
• Cold anesthesia can cause irreversible damage to olfactory receptors, leading to artefactual results.
• Proper anesthesia selection is critical for accurate insect sensory physiology research, especially for Vespa velutina nigrithorax alarm signaling.