Growing up, Clyde Sorenson loved catching bugs, especially fireflies. But even as a child, the budding entomologist saw that there was much more to these soft-bodied insects than most people thought. “I realized I had a pretty significant diversity of fireflies in my own 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 North Carolina’s Blue Ridge Mountains). One thing that has always fascinated him is why these little creatures light up. It’s a question many of us ponder. The answer, according to Sorenson, is surprisingly complex.

What are fireflies?

Despite their name, fireflies are not flies. either insects. They are actually bioluminescent beetles. This means that they produce light naturally through a different chemical reaction.

Their bodies contain a special organic compound called luciferin. This compound combines with oxygen and an enzyme known as luciferase in the lower abdomen of the insect, creating a biochemical reaction that produces light that varies in color from yellow and green to rare shades of blue.

Fireflies thrive in warm, humid regions, particularly around forests, fields and wetlands. In the United States, they live mainly east of the Rocky Mountains, although there are pockets of them 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.

The most common firefly in the eastern United States is Photinus pyralisalso known as the eastern firefly or the Big Dipper firefly.

“It’s the species that’s usually active when a lot of people are still sniffing around,” Sorenson says. They are also an easy species to catch, as eastern fireflies tend to fly slowly and low to the ground.

Why do fireflies glow?

“It depends on what stage of life you’re talking about,” Sorenson says. For example, firefly larvae blink to warn potential predators to stay away. “Their bright sheen signals to others that they taste bad,” Sorenson says. This defensive mechanism is known as an aposematic signal.

And fireflies (and many bioluminescent organisms) do tastes bad This is mainly due to a group of toxic steroids called lucibufagins. Lucibufagins can even be lethal to small lizards. Through a bit of trial and error, potential predators learn early on to avoid such illuminated prey.

But adult fireflies also blink to communicate with and attract members of their species. The ancestors of modern fireflies probably glowed only as larvae. But over tens of millions of years, adult insects adopted (borrowed and adapted) this ability to produce light in an intricate mating ritual.

“In most North American fireflies, males have a specific flashing pattern,” Sorenson says. “If they fly at the right time of night,” which is usually dusk, “and make the right signal, a female might see the signal and flash back.”

The two insects will approach each other and “maybe some kind of pheromonal communication will occur,” a type of chemical signal that says they are both ready for action. “Then if everyone is happy, they mate and no one shows anything for a while.”

This complex courtship is known as the “firefly mating dance.” Although the call and response system is common among species, the pattern used by each species is different.

For example, when the male eastern firefly flashes its J-shaped pattern approximately every five seconds, the female will respond with a half-second flash. The Elkmont area in Great Smoky Mountains National Park and Congaree National Park in South Carolina are home to synchronous species of fireflies. These wonderful beetles coordinate their flashing patterns to create large displays of synchronized light while mating. It often occurs at densities of hundreds, if not thousands, at a time.

Synchronous fireflies light up Congaree National Park #shorts #shortnews #news #localnews #fireflies

About three of the 2,000 species of fireflies synchronize their lights at the same time. Video: Synchronous fireflies illuminate Congaree National Park, @WACHFOX

Something to keep in mind: About a quarter of the world’s firefly species don’t produce light as adults, and those that do “look very, very similar,” Sorenson says. However, “if you are familiar with the different flash patterns, you can figure out the species.”

Meet the femmes fatales of fireflies

While fireflies’ mating dances are fun to watch, not all of them are innocent. “Femme fatale” fireflies are predatory beetles (mainly of the genus phototouris) that adopt the different flashing patterns of other firefly species to survive. These particular fireflies do not produce lucibufagins, those unappetizing steroids that keep predators away.

Instead, they fool male fireflies of other genera by imitating the flashing patterns of Fotino and Pyractomena females. Once they attract the males with their trickery, they eat them for dinner and absorb their shiny toxins with the food.

“The femme fatales then use those [glowing] chemicals to protect their eggs,” Sorenson says, “and to some extent to protect themselves from predators.”

The life cycle of a firefly

Unlike femme fatales, most fireflies eat most of their food as larvae. “As adults, their main job is to find and mate and make sure there are more fireflies for next year,” Sorenson says.

While the idea of ​​starving your mature self sounds pretty daunting, adulthood is a relatively short period among fireflies. 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 their nutrients through soft-bodied insects such as slugs and snails.

They then undergo complete metamorphosis, shedding their larval body to develop adult features such as wings and legs. This stage lasts a few more weeks and then it’s time to become adults. Once fully grown, fireflies have sex, lay eggs, and live large lives for anywhere from five days to a month. Then the cycle begins again.

Fireflies are extremely efficient.

What’s especially interesting about fireflies is that they convert almost 100 percent of their chemical energy into light. This means they lose almost no energy in the form of waste heat, a byproduct of many resources, from power plants to incandescent light bulbs.

“Basically, fireflies have figured out how to produce light in a very energy-efficient way,” Sorenson says. “The more I learn about these creatures, the more fascinating they become to me.”

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