Changes in the Visual Response and Thoracic Temperature of Locusta migratoria manilensis Stimulated by LED Spectral Light

ABSTRACT Swarms of locusts causes significant impacts on agricultural systems worldwide. Research has focused on different techniques to capture large numbers of locusts to avoid such swarms. The exploitation of locusts phototactic response has been one such technique. The current study investigated the impact of different light wavelengths and intensities on the visual and thoracic temperature responses of locusts. Our results showed that ultraviolet (UV), violet, and orange light stimulated the visual system of the locust and resulted in increases in thoracic temperature, orange light stimulated the visual response the most, violet light triggered the strongest response, and UV light resulted in a response of the longest duration. In terms of the impact on thoracic temperature, the different intensities of violet light caused the temperature to increase the most, followed by UV light and then orange light. Thus, the effect of the visual response on physiology (indicated by the change in thoracic temperature) was determined by the level of light intensity and wavelength. Increasing the stimulation time with increasing light intensity but with the same light wavelength exceeded the visual tolerance range of the insects and strengthened the visual stimulation effect. Our results also indicated that the length of exposure time was important in determining the visual response and thoracic temperature change, suggesting that these features are key to improving the phototactic impact of light treatment. Thus, our results could be useful in developing light-based treatments to help control locust populations via exploitation of their phototactic responses to different light sources.