This study investigated the effects of polarized and spectral light interactions on locust polarotaxic behavior and elucidated the regulatory mechanisms of polarized and spectral lights. Locust visual response effect was investigated using a combined light source system comprising linear detection polarization violet light with various spectrum lights and a response device to explore the interaction mechanism of polarized and spectral lights on locust visual sensitivity characteristics and the specific sensitivity of locust phototaxis and polartaxis. Results indicated that the polarized vector sensitivity of locusts was related to combined light intensity, showing high visual response sensitivity at 0° and 180° under 1000 lx, whereas under rated illumination (150 mW/cm²), the coupled spectrum attributes induced changes in the locusts’ sensitive vectors. UV, violet, and blue lights enhanced the sensitivity at 90° and 270°, and green and orange lights did so at 0° and 180°. Moreover, UV and violet lights enhanced the aggregation and trend sensitivity at 210° and 30°, blue, green and orange lights induced high sensitivity at 0° and 180°. Under increasing illumination, the enhanced effect of light intensity on aggregation sensitivity under blue, green, and orange spectra and on trend sensitivity under orange spectra at 90° and 270° was highly pronounced because of the interaction between heterogeneous spectrum illumination and linear detection polarization vector illumination. Meanwhile, the spectral attribute determined the locust visual response effect, which was affected by the linear detection polarization vector. When illumination increased to rated illumination, coupled light intensity induced a specific vector sensitivity related to optical distance, showing the strongest response sensitivity to 180° under orange spectra and the strongest aggregation and trend sensitivity to 210° under violet spectra due to the interplay of polarization degree, coupling light intensity, and specific vision sensitivity caused by partially polarized light. Then, the locust visual response effect was improved by utilizing the enhancement effect of polarized violet light coupled with violet light at a close range and the inductive effect of polarized violet light coupled with orange light at a long distance, which provides theoretical support for understanding locust polarotactic orientation mechanisms, facilitating the development of polarization-induced light sources for attracting locusts.

New approaches are required to prevent the plagues of locusts that threaten crop security in many areas of the world. One such approach is to exploit locusts’ polarotactic response effect, enabling their aggregation and effective removal from agricultural sites. The current study used linearly partially polarized light with different polarization vectors and a polarotactic response device to test locusts’ polarotactic response effect. Results showed that under partially polarized light with linear polarization vectors in the range of 0°-360°, locusts exhibited a sinusoidal-cosine tuning response in specific periods depending on the intensity of the polarization spectrum, and differences in the intensity of the polarization spectrum led to changes in the sensitivity of polarotactic vision at different distances. As the intensity of the illumination increased, the effects of polarized violet, blue, and orange spectra were strongest at far, medium, and close distances, respectively. At the maximum illumination intensity, the differences in the specific sensitivity vector modes at different vision distances were due to variations in the sensitivity of the visual response to the e-vector induced by the optical distance polarization effect of the heterogeneous spectrum. The polarotactic responses were stronger under violet spectrum at 330° and blue spectrum at 0° (360°), while the polarotactic response and aggregation sensitivity were stronger at 240° and the visual trend was sensitive to 180° under orange spectrum. Intriguingly, locusts had different sensitivity thresholds to the intensity of the polarization spectrum, where the polarotactic responses were equal for polarized violet light at a vector of 330° and light energy from various spectral sources. Therefore, combined stimulation with illumination by polarized violet and orange spectra can enhance locusts’ polarotactic response effect and regulate the sensitivity of locusts’ polarization vision, which provides theoretical support for understanding locusts’ polarotactic orientation mechanisms, thereby facilitating the development of polarization-induced light sources for attracting locusts.

To clarify the function effect of spectrum and linear polarization-coupled light on locusts’ induction, determine the influence factors of linearly polarized light on locusts’ polartactic characteristics, construct the technical characteristics of locusts’ polarization induction, and develop locusts’ polartactic induction photo-source, this study investigated the functional influence of spectral light and linear polarization-coupled light on locust phototactic and polartactic behavior. A linearly polarized light source system was used to determine the polartactic response of locusts induced by different linearly polarized vectors under normal light conditions. The results demonstrated that, within the context of spectral and linear polarization-coupled light, the visual response sensitivity of locusts was related to the spectral light intensity, being highest in response to orange light intensity. The visual aggregation and selective sensitivities of locusts were both influenced by spectral irradiation distance, with the violet spectrum inducing the strongest sensitivity in both cases. The polartactic chord function tuning response characteristics at different angles (0°-360°) were associated with linear polarization spectrum attributes. The polartactic response of locusts was related to changes in visual sensitivity resulting from the distance from the linear polarization light source, being optimal in response to the orange spectrum, whereas the violet spectrum induced the optimal visual and polartactic aggregation sensitivities. Furthermore, the specificity of chord function tuning response characteristics with periodic vector variations in a heterogeneous spectrum showed significant changes. An orange spectrum vector mode led to the most pronounced changes in response, whereas the violet spectrum vector mode exhibited the most significant changes in chord function properties. These variations in chord function and period induced by spectrum impacted the functional effect of linear polarization vector modes and reset the sensitive vector of locust polarization vision. Specifically, under the orange spectrum, locusts exhibited the highest polartactic response sensitivity at 330° vector, whereas, under the violet spectrum, the polartactic aggregation sensitivity was most pronounced at 30° vector, and visual trend sensitivity was optimal at 120° vector. Our results provide theoretical support for the study of the specific sensitivity nature of locust phototactic and polartactic behaviors, and the construction of a mechanism for inducing the polarization spectrum in locusts.

New approaches are required to prevent the plagues of locusts that threaten crop security in many areas of the world. One such approach is to exploit the phototactic response of locusts, enabling their aggregation and effective removal from agricultural sites. This study examined the effect of the dorsal rim area (DRA) of the locust compound eye on the phototactic response of locusts to spectral light. Locusts with intact DRA showed increased phototactic responses to blue, green or orange light but decreased responses to UV and violet light, whereas locusts with blacked-out DRA (non-DRA vision) showed the strongest phototactic responses to orange followed by violet light. The combined results revealed that phototactic push-pull effect triggered by responses of DRA versus non-DRA vision was strongest in response to violet light. Compound vision in the locust is the result of the synergism between DRA versus non-DRA vision, causing a push-pull phototactic effect that is most stimulated by exposure to violet light, with light intensity enhancing this effect. These results provide theoretical support for the induction of phototaxis and polarotaxis in response to light in locusts, which could be useful for the development of light-based control systems in the field.