Electrophysiological methods in insect olfaction: a review of EAG, GC-EAG, SSR and GC-SSR approaches

Abstract

Background: Insects rely on olfaction as a key sensory modality regulating reproduction, foraging, host location, and defense. Antennae function as highly sensitive chemosensory organs capable of detecting volatile organic compounds (VOCs) at trace levels, making them valuable for ecological research and biosensor development. Methods: This review examines electrophysiological techniques commonly applied to study insect olfaction, including electroantennography (EAG), gas chromatography–electroantennographic detection (GC-EAG), single sensillum recording (SSR), and gas chromatography–single sensillum recording (GC-SSR). The principles, applications, and recent technological innovations such as MEMS devices, biohybrid sensors, and advanced signal-processing methods are discussed. Results: EAG provides a low-cost method for recording cumulative antennal responses, while GC-EAG couples antennal activity with chemical separation to identify bioactive volatiles. SSR offers high-resolution measurements of individual olfactory receptor neu-rons, and GC-SSR extends this capability to complex odor blends. Together, these ap-proaches reveal complementary aspects of odor coding at both the antennal and sin-gle-neuron levels. Conclusions: Electrophysiological methods are indispensable tools in chemical ecology, pest management, pollination biology, and biosensor development. Future integration with emerging technologies is expected to deepen our understanding of insect olfaction and support sustainable biotechnological applications.