Opsin genes in diverse dragonflies. (A) Adult dragonflies representing 12 species and 11 families examined in this study. (B) Numbers of opsin genes of pteropsin type, RGR-like, arthropsin type, Rh7-like, UV type, SW type, and LW type mapped on the dragonfly phylogeny (76). Numbers of insect visual opsins (visual) are highlighted by purple for UV type, blue for SW type, and green for LW type. SW genes are further categorized into groups a, b, and c; so are LW genes into groups A, B, C, D, E, and F (also see Fig. S2). Estimated gains and losses of the opsin genes in the evolutionary course of the dragonflies are indicated on the branches.