Diurnal insects can select suitable oviposition sites by discriminating plant coloration. The long wavelength sensitive opsin (LW) gene is mainly for discriminating long wavelengths of colors in diurnal insects. However, the affection of coloration on oviposition selection and the roles of LW gene in nocturnal insects are unclear. Here, the questions were explored in Helicoverpa armigera (Lepidoptera, Noctuidae) using CRISPR/Cas9 gene editing technology and experiments of oviposition selection under different coloration backgrounds. To different brightness (achromatic white, grey, black), wild moths preferred to oviposit on higher-brightness background, while the LW mutant had no preference. To different colors, wild moths had no oviposition preference, while the LW mutant significantly reduced oviposition on long-wavelengths of colors (red, orange, yellow, and green) compared to blue and violet. When both brightness (white) and color (orange and green) cues were presented for oviposition, wild moths were more attracted to brightness than color, while LW mutant had no significant preference. For the coloration of young and old leaves, wild moths preferred to oviposit on coloration of young leaves that had a brighter light green, while LW mutant had no preference. Electroretinogram recordings showed that the responses of moths to different bright light or different color light were significantly decreased after knockout of LW, especially to the long-wavelengths. These results suggest that brightness is a more reliable cue rather than color for oviposition selection of nocturnal moth H. armigera in changing microhabitats and LW mediates the recognition of different brightness and long wavelengths.

昼夜昆虫可以通过辨别植物的颜色来选择合适的产卵地点。长波长敏感视蛋白（LW）基因主要用于区分昼夜昆虫的长波长颜色。然而，颜色对产卵选择的影响以及LW基因在夜行性昆虫中的作用尚不清楚。在这里，利用CRISPR/Cas9基因编辑技术和不同着色背景下的产卵选择实验，在棉铃虫（鳞翅目，夜蛾科）中探索了这些问题。对于不同的亮度（无色白、灰、黑），野蛾更喜欢在高亮度背景下产卵，而LW突变体没有偏好。对于不同的颜色，野生飞蛾没有产卵偏好，而与蓝色和紫色相比， LW突变体显着减少了长波长颜色（红色、橙色、黄色和绿色）的产卵量。当亮度（白色）和颜色（橙色和绿色）提示产卵时，野生飞蛾更喜欢亮度而不是颜色，而LW突变体没有明显的偏好。对于幼叶和老叶的着色，野蛾更喜欢在具有较亮的浅绿色的幼叶着色上产卵，而LW突变体没有偏好。视网膜电图记录显示，敲除LW后，飞蛾对不同强光或不同色光的反应明显降低，尤其是对长波长的反应。这些结果表明，在改变微生境的夜蛾棉铃虫产卵选择中，亮度是更可靠的线索，而不是颜色， LW介导了对不同亮度和长波长的识别。