Lampyridae, also known as fireflies or lightning bugs, produce glowing lights from their bodies to signal potential mates. Fireflies are common in tropical and temperate regions of the world, especially in swamps, marshes and moist woodland areas. The light produced by fireflies has been a source of fascination to humans for years. When a firefly is accidentally squished against a window, windshield or other surface, you will notice that its body will continue to glow for several minutes after the insect has died.
Any organism known to generate light is called bioluminescent. Bioluminescence in fireflies results from a chemical reaction between an enzyme (luciferase), a substrate (luciferin), ATP (an energy source) and oxygen. Mixing these four components together triggers the emission of the soft glow associated with fireflies. Fireflies possess different flash patterns and each species of firefly will have flash signals that differ in length and intensity.
Squishing a Bioluminescent Firefly
When a firefly is squished, its body will continue to emit a glow for up to 15 minutes after it has been killed. Scientists are still doing research to understand the exact mechanism for how a live firefly controls its glow, when a firefly has been smashed, the different reactants required for the chemical reaction to produce light are mixed together. The luciferase stored in the firefly's tail is exposed to other reactants, allowing for the reaction to continue even when the firefly is no longer living.
Squishing a Nonbioluminescent Firefly
If you squish a nonbioluminescent firefly, you will quickly learn that not all fireflies emit a glow after death. There are several nonbioluminescent firefly species that will not glow after being smashed or stepped on. This occurs because the species do not possess all of the reactants required for the chemical reaction to occur, most notably luciferase.
Squishing a firefly will likely lead to the release of lucibufagens, which are chemical agents within a firefly's body that are toxic to animals. When an animal ingests a firefly, it will likely spit out the insect because this agent will be released into the animal's mouth. When a firefly is squished, lucibufagens are released from the firefly's body. You will be able to detect the presence of this chemical by a pungent odor and a milky white fluid seen within the insect's body.