Lightning bugs refer to many types of beetles that use bioluminescent flashing in order to attract females, or to respond to the flashes of light caused by males ready to mate. They may also be called fireflies, and a host of other names, but are never called glowworms. Glowworms are also beetles that use bioluminescence, but they are from a different family than lighting bugs.
Lightning bugs can be found around the world, and include over 2000 different species. They are most often found in marshes or wooded environments and prosper best in tropical or warm climates. The immature fireflies typically go unnoticed, often making their homes under bark or mud until they are fully mature. However, one can occasionally see pre-adult fireflies making small flashes on the ground.
When nocturnal fireflies reach maturity, it is often an amazing sight to see the air suddenly filled with flashing, flying beetles. Many lightning bugs actually don’t flash, or their flashes go unnoticed because they are diurnal. All fireflies do glow when they are in the larval stage, even if they don’t get to flash as adults.
The actual flash process is a result of a chemical reaction in the abdomen of lightning bugs. They secrete two enzymes called luciferase and luciferin, which when combined, cause small flashes of light. In some cases, only one sex will be able to produce light. In other species, males looking to mate send out flash signals to females. The females may then respond with a flash of their own if they are ready to mate.
What is quite amazing, given the number of lightning bug species, is that each species has its own distinct flash. Therefore, lightening bugs generally only signal or are responded to by their own species. Some fireflies are an exception to this rule. Photuris lightning bugs actually use flashes that duplicate the flashing of other species, bringing male fireflies ready to mate right to the Photuris female. She actually uses this for predation, and eats gullible males that respond to her signal.
Adult fireflies can be fun to watch, and are not considered pests. They tend to eat either pollen or nectar, which promotes plant growth. Larvae are likely to eat slugs and snails, or sometimes other larva. This too is helpful to people who want pesticide-free ways of keeping slugs and snails out of their garden.