What to Know About Lightning Bugs

Medically Reviewed by Sanjay Ponkshe on June 03, 2024
4 min read

Lightning bugs, more commonly known as fireflies, are winged beetles that produce luminous effects. These bugs have 2,000 about species worldwide, with more than 150 present in the United States. The Great Lakes area alone has about two dozen lightning bug species.

Wisconsin sees a massive light show of fireflies in June, July, and August. These bugs are seen as a sign of romanticism.

Lightning bugs are found primarily in moderate and tropical regions. They generally don't bite humans, so these bugs are harmless.

Lightning bugs are not actually bugs or flies, but they are beetles from the Lampyridae family. Firefly is a common name used for these luminous insects. 

North America hosts around 23 genera and 200 species of lightning bugs. They can be present in tropical as well as subtropical areas.  In the U.S., fireflies are usually rare west of Kansas. 

These flying insects don't have hard forewings (elytra) like many beetles. Their elytra are more flexible and soft.

The adult lightning bugs rest in the daytime and come out around dusk or midnight. Female fireflies mostly lay eggs in damp places in the soil. The larvae stay in the ground throughout winter and then pupate in spring.

Some lightning bugs are carnivorous. Their larvae feed on slugs, worms, and snails by injecting their chemicals into their prey. Adult fireflies eat pollen, other lightning bugs, or nectar to survive. Some surprisingly don't eat anything at all.

Lightning bugs are luminous flies with wings, but some female fireflies are wingless. They are about one inch long. People more commonly call them glow worms due to their highly-efficient glowing ability.

Male and female fireflies create reddish-orange to greenish-yellow light. These light-producing organs are present under their abdomens. They produce cold light as there is no heat produced in the process.

The light intensity and pattern may vary from one species to another. Some species may also flash at the same time. You can easily identify males and females due to these flashes.

Male fireflies use flashes to signal females for mating. 

Lightning bugs usually live in temperate and tropical areas in every corner of the world except Antarctica. 

They can be found in parks, gardens, wooded areas, and meadows in the evening and night. There is no specific habitat for fireflies as they are scattered everywhere. 

Lightning bugs don't have pincers, so they can't bite. These insects don't transfer any disease to humans and are harmless. They don't fly as fast as other flies or insects. 

Larvae of fireflies are predators. They attack other insects, such as snails and slugs, and their larvae to survive. Larvae of some species also feed on earthworms. In some species, adults can also be predatory.

Lightning bugs contain two special chemicals, luciferase and luciferin. These are usually used in cancer, cystic fibrosis, and cardiac disease research. Some species of fireflies can also release defensive steroids known as lucibufagins. 

So are lightning bugs poisonous? Yes, fireflies can be poisonous to their predators. Lucibufagins are toxic chemicals that some animals release when they are in danger. 

Fireflies having lucibufagins usually build a powerful defense against several predators, including bats, mice, and spiders. Not all fireflies contain these steroids.

Here are some interesting lightning bug facts:

Fireflies Are Not Flies

Fireflies are beetles. They are neither bugs nor flies. They belong to the Lampyridae family, a Greek name meaning "to shine." Some fireflies glow, while others may not glow. Most of them are winged, but the females can be wingless. 

Winged fireflies differentiate themselves from glowworms. But they come under the name glowworm, along with several other species.

Lightning Bugs are Very Efficient

Not all fireflies can glow. Some don't mix oxygen with luciferin (a pigment) to produce light with little heat. This pigment works with an enzyme, luciferase, to create light in the presence of adenosine triphosphate (ATP), magnesium ions, and oxygen. 

This light is super-efficient. Around 100% of the energy used in the chemical reaction turns into light, so there is no energy waste. 

Fireflies use this light for synchronized flashy displays. This phenomenon more commonly happens in Southeast Asia but can also occur in Tennessee in June.

Fireflies Ward off Predators With their Light

The biggest benefit of light for fireflies is that they can use it to ward off predators. The lucibufagins make these insects distasteful to their predators. When their predators bite them, they get the taste of lucibufagins and prevent attacking those fireflies again in the future. 

Firefly Flashes Are Often Considered Romantic

Each firefly species flashes differently. This pattern helps them search for potential mating partners. Male fireflies use a specific flashing pattern while flying in the air finding a female. 

Many lightning bugs flash only once, while others do so around nine to 10 times. Females stay on the ground waiting for an appropriate flash display. When females are interested, they flash only one time to express their willingness. This is done in a specific way.

Some female fireflies belonging to the genus Photuris act like the females from Photinus. They do so to attract the males from the Photinus genus and kill them in the process. These females also incorporate distasteful chemicals in the Photinus fireflies.

Many Fireflies Feed on Other Fireflies

The larvae of fireflies are predatory. They feed on other insects like snails, slugs, worms, and even other fireflies for their nourishment. Adult fireflies also eat nectar and pollen to survive. The fireflies species that are carnivorous spend all their life eating other fireflies. Some even don't eat anything at all.

Fireflies Are Becoming Extinct

Lightning bugs are unfortunately becoming extinct. Humans have created light pollution and built multiple habitats for fireflies, leading to a decline in the population of fireflies. Lightning bugs don't relocate. They disappear when someone takes over their habitat.

People usually romanticize lightning bugs, but they contribute to their extinction every day.