草地贪夜蛾Spodoptera frugiperda是世界性粮食作物重大害虫，被列入我国“一类农作物病虫害名录”。草地贪夜蛾存在与寄主植物相关的两种同域寄主型：偏好取食为害玉米、高粱等作物的玉米型和偏好取食为害水稻和牧草等作物的水稻型。且通过COⅠ和Tpi基因两种分子标记对我国不同地区采集样本的种群遗传特征进行分析，两种寄主型个体均有检出。寄主型的存在及其表型分化，提高了田间监测和害虫防治的复杂性和困难性。为此，本研究综述了国内外草地贪夜蛾不同寄主型种群在寄主适应性、行为、生理生化、抗性等各方面的表型分化及其寄主型形成机制的研究进展，并探讨了我国开展草地贪夜蛾寄主型分化及形成机制研究的意义，旨在为我国进一步完善草地贪夜蛾防控体系，合理规避危害损失提供依据。

The fall armyworm (FAW), Spodoptera frugiperda (Smith), is one of the main global pests of food crops, and is on the "List of Class I Crop Diseases and Pests" in China. There are two sympatric strains, one which prefers to feed on corn and sorghum (the corn strain; CS), and another that prefers to feed on rice and pasture grasses (the rice strain; RS). Two molecular markers, the COⅠ and Tpi genes, were used to analyze the population genetic characteristics of samples collected from different parts of China. Individuals from both host strains were detected. The existence of different host strains, and the phenotypic differentiation between these, increases the complexity and difficulty of monitoring and controlling this pest. This paper summarizes progress in research on phenotypic differentiation, host adaptability, behavior, physiology, biochemistry, resistance, and other aspects, between the two FAW host strains, and the mechanism by which host strains form, both domestically and internationally. Furthermore, we discuss the significance of studying the population differentiation and formation of host strains in China. The purpose of this paper is to further enhance the prevention and control of the FAW in China, thereby preventing significant crop damage and economic loss.