Fig. 3 External morphology, ultrastructure and the response of compound eyes of Megalurothrips usitatus under different wavelengths. (a) Microscopic observation of visual receptors of Megalurothrips usitatus (I) Ventral view of head; Ant: Antenna; CE: Compound eye. (II) Dorsal view of head; TS: Trichoid sensillum; Om: Ommatidium; DO: Dorsal ocellus; DRA: Dorsal rim area. (III) Lateral view of head; OB: ocellar bristles; DO: Dorsal ocellus; Om: Ommatidium; TS: Trichoid sensillum. (b) Fluorescent area of Megalurothrips usitatus compound eyes irradiated by UNA (360 nm-370 nm), BVW (400 nm-440 nm), BNA (470 nm-495 nm) and GW (530 nm-550 nm) in the front, dorsal and lateral view. The triangles (▲) mark the position of the UV-sensitive ommatidium. (c) The images of computer vision aided analysis by OpenCV. (I) The original image which shows the fluorescent area of Megalurothrips usitatus compound eyes irradiated by UNA in the lateral view. (II) A grayscale image of the original luminance channel. (III) The image with clear fluorescent responsive areas morphologically processed of the L channel image. (IV) The binary image binarized from Fig. 3C-III. (V) The contours of the mask (VI) Left panel shows the luminance values for ten points located in the UVsensitive ommatidium areas and the position coordinates of the corresponding points, and right panel is the corresponding image. (VII) Left panel shows the luminance values for ten points located in the clear fluorescent responsive areas chosen by OpenCV with box and the position coordinates of the corresponding points, and right panel is the corresponding image with blue boxes.