Data from: Plant odour and sex pheromone are integral elements of specific mate recognition in an insect herbivore

Specific mate recognition relies on the chemical senses in most animals, and especially in nocturnal insects. Two signal types mediate premating olfactory communication in terrestrial habitats: sex pheromones, which blend into an atmosphere of plant odorants. We show that host plant volatiles affect the perception of sex pheromone in males of the African cotton leafworm Spodoptera littoralis and that pheromone and plant volatiles are not perceived as independent messages. In clean air, S. littoralis males are attracted to single synthetic pheromone components or even the pheromone of a sibling species, Oriental cotton leafworm S. litura. Presence of host plant volatiles, however, reduces the male response to deficient or heterospecific pheromone signals. That plant cues enhance discrimination of sex pheromone quality confirms the idea that specific mate recognition in noctuid moths has evolved in concert with adaptation to host plants. Shifts in either female host preference or sex pheromone biosynthesis give rise to new communication channels that have the potential to initiate or contribute to reproductive isolation.

绝大多数动物，尤其是夜行性昆虫（nocturnal insects）的特异性配偶识别（specific mate recognition）依赖于化学感官（chemical senses）。陆地生境中的交配前嗅觉通讯（premating olfactory communication）由两类信号介导：其一为性信息素（sex pheromones），这类信号混杂于植物气味分子（plant odorants）构成的环境氛围中；其二为寄主植物挥发物（host plant volatiles）。本研究发现，寄主植物挥发物会影响非洲棉叶蛾（African cotton leafworm，Spodoptera littoralis）雄虫对性信息素的感知，且性信息素与植物挥发物并非作为独立信号被感知。在洁净空气中，非洲棉叶蛾雄虫会被单一合成信息素组分甚至姊妹种东方棉叶蛾（Oriental cotton leafworm，S. litura）的性信息素所吸引；但当存在寄主植物挥发物时，雄虫对缺陷型或异种信息素信号的响应会被显著削弱。植物线索增强了雄虫对性信息素质量的识别分辨能力，这验证了夜蛾科（noctuid moths）昆虫的特异性配偶识别是与寄主植物适应协同演化而来的这一假说。雌性寄主偏好（host preference）或性信息素生物合成（sex pheromone biosynthesis）的改变，均可催生新的通讯通路，这些通路有可能引发或促进生殖隔离（reproductive isolation）的形成。