Lightning Bugs Making Their Annual Appearance
Watching and Catching Them is a Favorite Summer Activity
Jul 2, 2009
For countless kids over the generations, catching these largely nocturnal insects and placing them in glass jars for the enjoyment of watching them flash their lights on and off has been a familiar and fun summer evening activity.
But just sitting quietly on the porch looking out into the approaching darkness and watching them light up the night in a laser-light sort of visual symphony will provide a new and different appreciation for the true wonders of nature they really are.
Fireflies Not Really Flies
Fireflies are actually winged beetles and are not members of the fly family at all. Officially, they are in the insect family lampyridae within the beetle order Coleoptera.
There are an estimated 2,000 species found throughout the world, living predominantly in temperate and tropical climates. Generally, they prefer marshland and moist, wooded habitats. However, a few species are reported to inhabit arid climates.
Glowing Process Called Bioluminescence
Lightning bugs get their name from their unique ability to illuminate their lower abdomens in a process called bioluminescence. They employ this mechanism mostly to attract mates, but sometimes to lure prey or to signal to other predators that they will not be tasty if consumed.
Bioluminescence is the result of a chemical reaction that occurs when a certain enzyme produced by the firefly called luciferase combines with other elements, including oxygen and adenosine triphosphate (ATP). This combination triggers the activation of photic cells located in their abdomens that flash on and off in patterns that are species-specific.
Scientists have estimated that nearly 90% of the energy a firefly uses to create this phenomenon is converted to visible light in a highly efficient process that produces almost no heat. Known as “cold light,” it has no measurable ultraviolet or infrared rays.
Flashing For Mates and Prey
In most North American species, the nocturnal flashing is typically initiated by adult males in search of a female for mating purposes. Females indicate their interest and respond to these signals by flashing back their own code. They carry on a back-and-forth visual courtship that culminates with the female’s selection of the mate that most impresses her with his performance.
Firefly larvae also have the ability to glow, but in their case, it is used primarily to ward off any predators. It is used as a warning signal, sending a message that the chemicals in its body that create this luminosity are toxic and unappetizing.
Producing light, especially in the early stages of life, takes energy. While in the larvae stage, fireflies will prey on worms, snails and slugs by injecting them with a numbing anesthetic that allows them to be slowly digested.
Adults sustain themselves mostly with plant pollen and nectar, although some adults don’t eat at all.
Some female species are known to mimic the flashing patterns of other species to first attract and then prey on them, though not necessarily for sustenance. In these cases, it is believed that the predator species does not naturally possess the chemicals necessary for bioluminescence and preys on other species in order to acquire them.
