Temporal dynamics of antennal responses encode plant stress and ecological relevance in Spodoptera littoralis moths

Polyphagous insects draw fitness-relevant information from complex plant odor blends, yet electroantennography (EAG) studies often emphasize response amplitude rather than temporal structure. We combined natural plant volatile stimuli, temporal EAG analysis, and machine-learning classification to examine the responses of male and female Spodoptera littoralis antennae to host/edible plants, non-hosts, and drought-stressed plants. EAGs entailed much information about plant volatiles. Female responses showed stronger functional organization and higher classification performance for the above-mentioned categories, particularly for non-host plants, whereas males retained discrimination only under high-contrast stress conditions. These findings suggest that peripheral antennal dynamics preserve biologically relevant information about plant suitability and physiological state. More broadly, this framework offers a new approach for linking peripheral olfactory physiology with future electrophysiological and behavioral experiments.