THE CHEMICAL MECHANISM AND EVOLUTIONARY DEVELOPMENT OF BEETLE BIOLUMINESCENCE

Bioluminescence, as a phenotype, has many evolutionary origins, and thus is an example of natural reinvention many times over. Although peculiar, it arises from the same biochemical principles and evolutionary mechanisms as other biochemical reactions. Of these many different bioluminescent systems, that of the luminous beetles is one of the best understood, having been extensively studied for over 50 years. The luminescence ensues from oxidation of a molecule unique to luminous beetles, beetle luciferin, through a catalytic mechanism evolved from ancestral coenzyme A synthetases. Thus, the character of this bioluminescent reaction is in part a consequence of that evolutionary history. Beetle bioluminescence is furthermore unusual in having a range of luminescent colors found among different beetle species and sometimes even within individual beetles. Structural features of the luciferases are responsible for these color differences, although the underlying mechanism is not yet clear.