The firefly uses chemiluminescence
to produce light and attract a mate. The reaction occurs inside the living
organism and is known as bioluminescence. They produce light
via a chemical reaction consisting of Luciferin (a substrate) combined with
Luciferase (an enzyme), ATP (adenosine triphosphate) and oxygen. When these
components are added, light is produced. McElroy
(1951) described the reaction as: