Why fireflies blink

Two chemicals found in their bodies, luciferin and luciferase, spur a reaction in the presence of oxygen, adenosine triphosphate ATP, which is found in all living things , and other compounds. Luciferin is heat resistant, while luciferase a bioluminescent enzyme spurs the emission of light , Harrison explains. Depending on the species, a male or female firefly can create light for a number of purposes.

First, it comes in handy during mating season, according to the National Park Service. Typically, the male will fly around sending light signals to a group of females seeking out the right partner, and each species has its own unique flash patterns. Once the female finds a male up to her standards—say, depending on how often he lights up and the intensity of the flash—she emits her own light and the rest is history, Harrison says.

And if they have a baby? But these so-called femme fatales can perform an array of robust flashes meant to mimic the come-hither calls of females from other firefly species. Desperate to mate, males soar in to investigate what looks like an amorous female of their own species, and are promptly devoured.

Sometimes, femme fatales will even take to the skies and hunt blinking males on-the-wing. This is known as hawking, and best observed while blasting Highway to the Danger Zone from some earbuds. Femme fatales have also been known to filch other fireflies that have become trapped in spider webs.

In fact, a firefly spends the vast majority of its life one to two years as a ravenous little larvae known as a glow-worm. These tiny, glowing predators prowl about the underbrush hunting for worms, slugs, snails and anything else they can seize with their mandibles and inject with a paralysis-inducing venom.

Fortunately, glow-worms are too teensy to bite us humans. Why all the ravenous ladies, then? Well, many firefly species possess chemical compounds that make them unappealing to predators.

This makes sense, given that lightning bugs are relatively slow-flying insects that flit about with the equivalent of a neon billboard on their butts. Without chemical weapons, they'd would be easy pickings for bats, birds, and a whole host of other predators. And while femme fatales have been found to produce at least some of these compounds on their own, Faust and her colleagues believe they acquire others through acts of cannibalism.

The females then pass these defenses onto their eggs and larvae. Potential mates are also on the menu. The light that fireflies produce may be green, yellow or orange in color. Occasionally, fireflies put their efficient light to good use in flashy displays. Some fireflies, most famously in Southeast Asia, will synchronize their flashes. In the U. Fireflies flash in patterns that are unique to each species. Each blinking pattern is used to help them find potential mates.

Male fireflies typically fly through the air in search of a female by emitting a species-specific flashing pattern. Some fireflies only flash once, while others do so up to nine times. The females sit on the ground and wait until they see an impressive light display. Less romantically, female fireflies in the genus Photuris mimic the flash of females in the genus Photinus attracting Photinus males, which they lure in to eat.

Fireflies probably originally evolved the ability to light up as a way to ward off predators, but now they mostly use this ability to find mates. Interestingly, not all fireflies produce light; there are several species that are day-flying and apparently rely on the odors of pheromones to find each other. Each firefly species has its own signaling system. In most North American species, the males fly around at the right height, in the right habitat and at the right time of night for their species, and flash a signal unique to their kind.

The females are sitting on the ground or in vegetation, watching for males. Then the two reciprocally signal as the male flies down to her. If everything goes right, they mate.

A good example is Photinus pyralis , a common backyard species often called the Big Dipper. A male flies at dusk about 3 feet off the ground. If she sees a fellow she likes, she waits two seconds before making a half second flash of her own at the third second. Firefly light communication can get much more complicated; some species have multiple signaling systems, and some might use their light organs for other purposes.

While most male fireflies do their own thing and flash independently of other males of the same species, there are those that synchronize their flashes when there are many others around. In both these species, scientists think the males synchronize so everyone has a chance to look for females, and for females to signal males.