【目的】 旨在明确草地贪夜蛾Spodoptera frugiperda在玉米和高粱上的产卵选择性和寄主适合度，为草地贪夜蛾的科学防控提供依据。【方法】 在室内25 ℃条件下，采用叶片饲养观察的方法，比较草地贪夜蛾在玉米和高粱上的产卵量、取食量以及食物利用效率，并构建实验种群生命表。【结果】 草地贪夜蛾偏好在玉米叶片背面产卵，其平均卵块数最多，达到（3.40±0.55）块，且平均产卵量达到（346.00± 72.55）粒。取食玉米的草地贪夜蛾幼虫存活率显著高于取食高粱的（P<0.05），两者的平均存活率分别为98.89%和86.78%；在取食后5、6和7 d时，取食玉米的草地贪夜蛾幼虫食物利用效率显著高于取食高粱的（P<0.05）；取食玉米的草地贪夜蛾幼虫发育总历期显著短于取食高粱的（P<0.05）；在生命表参数比较中，取食玉米的草地贪夜蛾种群的净增殖率（R₀）显著高于取食高粱的（P<0.05），两者的平均净增殖率分别为（415.93 ± 69.69）和（372.45±34.70）。【结论】 草地贪夜蛾在玉米和高粱上均能完成生活史，玉米表现出更高的寄主适合度。但由于草地贪夜蛾在高粱上亦有较高的寄主适合度，且玉米和高粱生育期几近相同，因此在我国西南高粱种植面积较大地区，尤需提前防范草地贪夜蛾从玉米转移至高粱为害的风险。

[Objectives]  To determine the effect of feeding corn or sorghum on the oviposition site preference and fitness of the fall armyworm (Spodoptera frugiperda), and thereby provide information to improve the control of this pest. [Methods]  The oviposition preferences, survival, growth, reproduction, fecundity, food intake and efficiency of conversion of digested food (ECD) of S. frugiperda fed either corn or sorghum at a temperature of 25 were measured and compared, and a life table constructed from the data obtained. [Results]  S. frugiperda preferred to lay eggs on the back of corn leaves. The mean number of egg masses was (3.40±0.55), and the mean number of eggs was (346±72.55). A greater number of egg masses and eggs were laid on corn than on sorghum or other substrates. The survival rate of larvae fed on corn (98.89%) was significantly higher than that of those fed on sorghum (86.78%; P<0.05, one-way ANOVA). The ECD of corn-fed larvae was significantly higher than that of those fed on sorghum (P<0.05, one-way ANOVA) and the total developmental duration of corn-fed larvae was significantly shorter than that of sorghum-fed larvae (P<0.05, one-way ANOVA). Comparison of life table parameters indicates that the net reproductive rate (R₀) of corn-fed larvae was significantly higher than that of sorghum-fed larvae (P<0.05, one-way ANOVA). The average net reproductive rates (R₀) of corn and sorghum-fed larvae were (415.93±69.69) and (372.45±34.70), respectively. [Conclusion]  S. frugiperda can complete its life cycle on either corn or sorghum, but larvae raised on corn had higher fitness. However, because S. frugiperda can also complete its life-cycle on sorghum, and the corn and sorghum growing periods are almost the same, there is a risk of this pest spreading to sorghum from corn crops.