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As a child, Clyde Sorenson loved to catch bugs, especially fireflies. But even as a child, the aspiring entomologist saw that these soft-bodied insects were hiding much more than most people thought. “I noticed that I had a pretty significant diversity of fireflies in my yard,” Sorenson says, “so I started trying to understand that diversity.”
Sorenson, now a professor of entomology at North Carolina State University, has spent many years studying these magnificent creatures (he even helped discover a distinct population of fireflies in the Blue Ridge Mountains of North Carolina). One thing that always continued to fascinate him was why these little creatures glow. This is a question that many of us ponder. The answer, according to Sorenson, is surprisingly complex.
What are fireflies?
Despite their name, fireflies are not flies. or errors. They are actually bioluminescent beetles. This means that they naturally produce light through a specific chemical reaction.
Their bodies contain a special organic compound called luciferin. This compound combines with oxygen and an enzyme known as luciferase in the insect’s lower abdomen, creating a biochemical reaction that produces light that ranges in color from yellow and green to rare shades of blue.
Fireflies thrive in warm, humid regions, especially around forests, fields and wetlands. In the United States, they are primarily found east of the Rocky Mountains, although there are pockets in Utah, New Mexico and other western states. There are more than 2,000 recognized species of fireflies worldwide, with more than 170 species found throughout North America.
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The most common firefly in the eastern United States is Photinus pyramidisalso known as the eastern firefly or the great dipper firefly.
“This is a species that is usually active when there are a lot of people still hanging around,” Sorenson says. They are also easy to catch because eastern fireflies tend to fly slowly and low to the ground.
Why do fireflies glow?
“It depends on what life stage you’re talking about,” Sorenson says. For example, the blinking of firefly larvae warns potential predators to stay away. “Their bright glow signals to others that they have poor taste,” Sorenson says. This defense mechanism is known as aposematic signaling.
And fireflies (and many bioluminescent organisms) do bad taste. This is primarily due to a group of toxic steroids called lucibufagins. Lucibufagins can be lethal even to small lizards. Through trial and error, potential predators learn early on to avoid such illuminated prey.
But adult fireflies also blink to communicate and attract members of their own species. The ancestors of modern fireflies probably glowed only in the larval stage. But over tens of millions of years, adult insects borrowed (borrowed and adapted) this ability to produce light in an intricate mating ritual.
“In most North American fireflies, the males have a distinctive flash pattern,” Sorenson says. “If they fly at the right time of night,” usually at dusk, “and give the right signal, the female may see the signal and flash in response to it.”
Two insects approach each other, and “perhaps there is some kind of pheromonal communication going on,” a kind of chemical signal that says they are both ready for action. “Then if everyone is happy, they mate and no one shines for a while.”
This complex courtship process is known as the “firefly mating dance.” Although the call and response system is common to all species, the patterns each species uses are different.
For example, when a male eastern firefly flashes a J-shaped pattern approximately every five seconds, the female responds with a half-second flash. The Elkmont area of the Great Smoky Mountains National Park and Congaree National Park in South Carolina are home to synchronous firefly species. These wonderful beetles coordinate their blinking patterns to create huge flashes of synchronized light during mating. This often happens in hundreds, if not thousands, at once.
Synchronized fireflies light up Congaree National Park #shorts #shortnews #news #localnews #fireflies
About three of the 2,000 species of fireflies flash their lights in unison. Video: Synchronized fireflies light up Congaree National Park, @WACHFOX
It’s worth noting: About a quarter of the world’s firefly species don’t emit light as adults, and those that do “look very, very similar,” Sorenson says. However, “if you are familiar with the different flash patterns, you will be able to identify their type.”
Meet the firefly femme fatales
While the mating dances of fireflies are interesting to watch, not all of them are innocent. Fireflies “Femme Fatales” are predatory beetles (mainly of the genus Fotouris), which adopt the blinking patterns characteristic of other firefly species to survive. It’s these fireflies that don’t produce lucibufagins, those unappetizing steroids that repel predators.
Instead, they trick male fireflies of other genera by imitating the blinking patterns of male fireflies of other genera. Fotin And Pyractomena women. Having lured the males with their cunning, they eat them for dinner, absorbing their glowing toxins along with the food.
“Femme fatales then use these (luminous) chemicals to protect their eggs,” Sorenson says, “and to some extent protect themselves from predators.”
Firefly life cycle
Unlike femme fatales, most fireflies eat most of their food as larvae. “The main job of the adults is to find each other, mate, and make sure there are more fireflies next year,” Sorenson says.
While the idea of starving yourself as an adult sounds pretty grim, for fireflies, adulthood is a relatively short period of time. These beetles spend most of their life cycle—up to one or two years—as larvae buried in the soil, inside rotting wood or in leaf litter. Here they obtain nutrients through soft-bodied insects such as slugs and snails.
Fireflies spend most of their lives as larvae. Image: Getty Images/ Ivo Savov
After this, they undergo a complete metamorphosis, shedding their larval body and acquiring adult features such as wings and legs. This stage lasts for a few more weeks, and then it is time to become adults. As fireflies grow, they have sex, lay eggs, and live large for five days to a month. Then the cycle begins again.
Fireflies are extremely effective
What’s so cool about fireflies is that they convert almost 100 percent of their chemical energy into light. This means they lose almost no energy to wasting heat, a resource-intensive byproduct of everything from power plants to incandescent light bulbs.
“Essentially, fireflies figured out how to make light very energy efficient,” Sorenson says. “The more I learn about these creatures, the more fascinating they become to me.”
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Laura Kiniry is a freelance journalist based in San Francisco, California. Follow her on Instagram @laurajkin.