Oxygen toxicity aspects in luminescent and non-luminescent elaterid larvae

Abstract Superoxide dismutase (SOD) and catalase activities were determined in larvae of luminescent and non-luminescent click-beetles (Elateridae). Superoxide dismutase levels were found to be 5- ( Pyrophorus divergens and an unidentified Pyrophorinae) and 15- ( Pyrearinus termitilluminans ) fold higher in the luminescent insects. Regarding catalase, the data show that P. divergens and the unidentified species are richer (1.7 and 3-fold, respectively), whereas P. termitilluminans is poorer (0.7-fold) in this enzyme than non-luminescent Elateridae. For luminescent larvae, a direct correlation between SOD activity and brightness from the segments of their body (thoracic or abdominal) was observed. The results are interpreted in terms of SOD protection against deleterious effects of active oxygen species arising from storage of molecular oxygen to sustain the bioluminescent reaction.