The compound eye structure, phototactic traits and opsin gene-mediating photosensitive mechanism in Nilaparvata...

Nilaparvata lugens is a major rice pest in Asia, exhibiting significant phototactic behavior, which plays a critical role in its migration and colonization. However, the response characteristics of N. lugens to different light wavelengths and its underlying molecular mechanisms are unclear. This study aims to investigate visual structure, the phototaxis and opsin gene functions in N. lugens to provide a theoretical basis for developing new vision-based physical control techniques.

Female N. lugens exhibited more ommatidia (501.3 vs. 470.7), larger ommatidial size (277.4 vs. 253.1 μm²), and higher relative pigment content per ommatidium compared to males. Prolonging light exposure (15-60 min) increased phototaxis rate from 45.3% to 69.3%, and raising intensity (80-400 lx) increased it from 38.0% to 69.3%. Extended dark adaptation induced a biphasic response, initially decreasing and then increasing the phototaxis rate (56.0% to 42.7% to 69.3%). Furthermore, the spectral sensitivity of the N. lugens was found as follows: 460 nm > 520 nm > 365 nm > 560 nm. Silencing UV1 or UV2 significantly reduced phototaxis rate under 365 nm UV light, while silencing LW markedly decreased phototaxis rate under 460 nm blue light, 520 nm green light, and 560 nm yellow light.

This study indicates that sex-specific differences in compound eye morphology of N. lugens correlate with differential phototactic responses to 560 nm light. N. lugens is the most sensitive to 460 nm blue light and that its phototaxis is modulated by light exposure duration, dark adaptation, and intensity. Moreover, we verified that UV1, UV2, and LW are essential for mediating visual responses to specific wavelengths in N. lugens. © 2026 Society of Chemical Industry.