The role of opsin genes in mediating phototaxis and color preference in the green peach aphid, Myzus persicae (Sulzer).

BACKGROUND: Insect light traps and color sticky traps are widely used to monitor and control pests based on phototaxis, but the role of opsin genes in regulating phototaxis and color preference in Myzus persicae remains poorly understood. RESULTS: The M. persicae showed stronger phototactic response to green light than to yellow light, yet preferred yellow cardboard. Four opsin genes (MpLW, MpUV1, MpUV2, and MpUV-Like) were cloned and characterized, revealing distinct spatiotemporal expression patterns. Ultraviolet (UV) irradiation induced MpUV1, MpUV2, and MpUV-Like expression, whereas green and yellow light preferentially up-regulated MpLW. RNA interference combined with wavelength-specific behavioral assays demonstrated that MpUV1 and MpUV2 are essential for UV-mediated phototaxis, while MpLW governs phototactic responses to long-wavelength light. Our results indicated that knockdown of either MpUV1 or MpUV2 significantly reduced the phototactic response of M. persicae to UV light, while knockdown of MpLW significantly reduced its response to both green and yellow light. Furthermore, the combined knockdown of all three opsins (MpUV1, MpUV2 and MpLW) led to a significant reduction in the phototactic response to both green and yellow light. Notably, in color preference assays, the MpLW knockdown alone did not significantly affect the aphids' choice between yellow and green cardboard, whereas the combined knockdown markedly reduced their attraction to both colors. CONCLUSION: These results demonstrate the differences in phototaxis and color preference regulation mechanisms of peach aphids, revealing that their visual system may employ refined and differentiated molecular strategies in response to different light stimuli. Our findings provide a novel perspective for developing pest management strategies based on insect vision. © 2026 Society of Chemical Industry.