Figure 1. Merged image of a male damselfly Ischnura senegalensis (Rambur, 1842).

The PL and optical images in the left and right-hand panels show the male damselfly and its various colored-body portions. Only the PL image shows the PL emissions from the colored-body portions that perform as special color signals. The insets display high-magnification PL and optical images of the compound eyes, thorax front, eighth abdominal segment, and wings, respectively. In the high-magnification optical images, the compound eyes, thorax front, and wings appear light green, but the eighth abdominal segment is light blue. In the high-magnification PL images, all the colors of these body parts, compound eyes, thorax front, eighth abdominal segment, and wings, look light blue, verifying that the PL emissions have a strong effect on the colors and coloration.