The contents of firefly luciferin in luminous and non-luminous beetles were determined by the methods of HPLC with fluorescence detection and the luminescence reaction of luciferin and firefly luciferase. Luminous cantharoids and elaterids contained various amounts of luciferin in the range of pmol to hundreds of nmol, but no luciferin was detected in the non-luminous cantharoids and elaterids.
