When laterality fails: sublethal cyclosporin-A exposure impairs courtship and reproduction in Ostrinia furnacalis

Lateralized courtship and mating behaviors in the Asian corn borer (Ostrinia furnacalis (Guenee)) play a key role in reproductive performance, yet their vulnerability to sublethal stressors remains poorly understood. Here, we investigated the effects of sublethal cyclosporin A (CsA) exposure on lateralized courtship behavior and reproductive performance. Adult males and females were assigned to 4 mating groups-unexposed males × exposed females, exposed males × unexposed females, exposed males × exposed females, and unexposed males × unexposed females and were fed diets containing sublethal concentrations (48 µg/g for 48 hours) of CsA according to their mating assignment. Our results showed that when exposed females mated with unexposed males, left-biased directional turning males (leftward 180° copulatory turn to achieve genital alignment) exhibited faster mate recognition, longer copulation durations, and induced greater female motionlessness, while right-biased directional turning males (rightward 180° copulatory turn to achieve genital alignment) made more frequent mating attempts and produced longer ultrasonic courtship songs, which were associated with higher female rejection. In the exposed females, regardless of male exposure, left-biased turning males achieved longer copulation and greater female receptivity, whereas right-biased turning males exhibited increased aggression and courtship effort but with reduced mating success. Among unexposed pairs, left-biased turning males were more efficient in mate recognition and evoked higher levels of female motionlessness than right-biased turning males. Across treatments, prolonged copulation occurred specifically in CsA-exposed males, regardless of female exposure, compared with unexposed males. Our findings demonstrate that lateralization enhances mating success in O. furnacalis, but sublethal chemical exposure disrupts this advantage, selectively impairing reproductive outcomes. This underscores the need for ecologically realistic studies to assess the broader fitness consequences of such neuromodulatory disturbances.