Before delving into the details of how fireflies produce light, it may help to know what this insect actually is. There is something very peaceful about sitting outside on the deck on a hot summer evening and watching the fireflies dancing around the yard. What happens when light goes out?” As a professor at Tufts University, Lewis has been lucky enough to answer some of those questions. No, I've never noticed that. In a surprising twist, Lewis and her colleagues found that while mating the male deposits not just sperm, but also a nutrient-filled package they’ve named the “nuptial gift.” This is what the females are really looking for — the long flashes of light helps to predict which males can provide lots of nutrients. A male flies at dusk about three feet (.9 meters) off the ground. A chemical reaction in the beetle’s abdomen gives it its bioluminescence. They look like actual worms, and they hang out in the grass and in caves. If that habitat is disrupted during their youth, populations can be extinguished. In regions with a large firefly population, some people greatly enjoy wandering around in marshes and woods as dusk, when they come out in large masses. Some species may “call” for many hours a night, while others flash for only 20 minutes or so right at dusk. A colleague of mine once put a firefly in his mouth – and his mouth went numb for an hour! Image via Clyde Sorenson. When the oxygen runs out, the glowing stops. I've also heard that the stronger the flash and the more rapid it is, the more attractive the firefly is to potential mates. I love fireflies. They rely on that habitat remaining undisturbed for the year or more it takes them to complete their life cycles. Sign up for our daily or weekly emails to receive The mechanics of this biological feat are well understood, although the reasons are a bit more murky. That's why fireflies constantly light up and then light off. Lewis is particularly taken by this idea: “The luminous displays are actually the silent love songs of male fireflies. My three year old grandson would probably take issue with that. I grew up in Ohio and we used to get lots of them at dusk in the summer. I always thought that they just light up periodically, regardless of whether they're still or moving. Her obsession began in grad school, sitting in a backyard in North Carolina and watching the sparks light up around her. Pay attention to the fireflies in your neighborhood; observe their flash patterns and behavior. Each firefly species has its own signaling system. A few remarkable facts about them: But, asks Lewis, how could lighting up have benefited early fireflies? Many Photuris fireflies can’t manufacture these defensive chemicals. The females are sitting on the ground or in vegetation, watching for males. However, one branch has lost its ability to produce this toxin. Are the gentle blinks of fireflies flashing a favorite part of your summer evenings? It turns out that the light first originated in the larval stage of fireflies. So when the oxygen is transported into the organ, the light is produced. I saw some in the grass one night while I was out in the swimming pool. Most fireflies are habitat specialists, using woodlands, meadows and marshes. Read the original article. 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. Our biology teacher finally ruined this story for us with the truth. Still, we thought it was really poetic, and we were grateful to him imparting this bit of his imagination to us. Adding to this vulnerability is the fact that the females of many species – like the famous blue ghosts of the southern Appalachians and elsewhere – are wingless and can’t disperse any further than they can walk. They don't fly. There is also a dark side. There is much yet to learn about fireflies. Some species can mimic the signals of other species so that they can attract a source of food. The resulting light is sometimes called “cold light,” since it generates no infrared or ultraviolet rays. They light up by a tightly orchestrated chemical reaction, involving the wonderfully named luciferase She wondered, “How do these creatures make light? I live in the Midwest where we have a lot of lightning bugs. It seems that the lights first evolved as a warning — danger! Image via Japan’s Fireworks/Shutterstock.com. 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. Then the two reciprocally signal as the male flies down to her. Habitat destruction is therefore one of the greatest threats to fireflies. “As we work together to craft a planetary future, I hope we can work together to keep these bright lights shining.”, Top 5 Talks at TED 2014 in Vancouver | Vancouver Homes, There are more than 2000 firefly species that have evolved very different courtship styles. Other species are diurnal, and some beetles in this family cannot produce light because they have adapted for life during the day. Fireflies emit flashes of light and even synchronize their glowing patterns with other lightning bugs. Are they talking to each other? Her husband tried to catch a few of them and show them to her up close, but that even made it worse. Here’s why they produce bioluminescence every summer. If everything goes right, they mate. 150 million years ago they flew during the day and didn’t light up. In other species only the males light up, and in yet others, both do. In North America, the two most famous species that do this are the Photinus carolinus of the Appalachian Mountains, including in Great Smoky Mountains National Park, and the Photuris frontalis that light up places like Congaree National Park in South Carolina. Those larvae make nasty-tasting chemicals to protect themselves from predators. notifications whenever new talks are published. They light up by a tightly orchestrated chemical reaction, involving the wonderfully named luciferase. I always thought that they just light up periodically, regardless of whether they're still or moving. Fireflies appear to light up for a variety of reasons. You mentioned they don't taste good so predators avoid eating them. But there are many different types and each type has their own patter of flashing. Later, that same light system evolved to be a part of complex courtship rituals. I usually see them light up every few seconds or so and they continue to glow for a few seconds at a time too. Wikibuy Review: A Free Tool That Saves You Time and Money, 15 Creative Ways to Save Money That Actually Work. @anon144095-- Do you mean that they only light up when they're flying up? While all fireflies light up in their larval forms, there are many species of fireflies that do not use light as an adult mating signal. Even now, I catch myself staring into the distance at dusk, hoping for the first sign of summer. Fireflies appear to produce other defensive chemicals, too, some of which may contribute to their distinctive smell. Are they talking to each other? Her obsession began in grad school, sitting in a backyard in North Carolina and watching the sparks light up around her. By Clyde Sorenson, North Carolina State University. I've always likened their glowing part to a light bulb! She finishes by saying, “As we work together to craft a planetary future, I hope we can work together to keep these bright lights shining.”, Pingback: Top 5 Talks at TED 2014 in Vancouver | Vancouver Homes. We tend to think of fireflies as one group of beetles. Fireflies are found widely across North America, including many places in the west, but they are most abundant and diverse in the eastern half of the continent, from Florida to southern Canada. @feruze-- Do you know why fireflies glow periodically? Members of the EarthSky community - including scientists, as well as science and nature writers from across the globe - weigh in on what's important to them.