How to Find and Catch Fireflies, According to a Firefly Expert

Few insects excite kids as much as fireflies. And it’s hard to imagine a more quintessential summer activity than catching them. Who doesn’t have fond childhood memories of roaming the backyard on a muggy July night, Mason jar in hand as you raced against friends to see who could catch the most before your parents called you in for the night? Fireflies are nature’s fireworks, and every night across a large swath of the United States, they put on a stunning spectacle.

Except fireflies aren’t actually flies at all ⏤ they’re beetles, and they are among the most popular insects in the world. Also known as lightning bugs or glowworms, there are three main types in the US ⏤ Photinus, Photuris, and Pyractomena ⏤ and they blink both to attract mates and fend off predators. And while toxic to some animals, they’re harmless to humans. These flying chemistry labs are among our most iconic critters, and catching them is a fun, simple way to get kids interested in nature and excited about science.

But where are your most likely to find fireflies? What’s the best way to catch them? And do they make good pets? Here’s everything you need to know to help kids enjoy the summer light show.

Where In The Country Do Fireflies Live

While fireflies are fairly widespread in North America, they’re far more prevalent in the eastern part of the country. The closer you get to the Rocky Mountains, the rarer they get. That doesn’t mean folks in the West are out of luck — there are pockets of fireflies in states like Arizona, Colorado, Nebraska, and the Dakotas — it’s just harder to spot them. To see if you live in an area rich with fireflies, check out this map from the Massachusetts Audubon Society’s Firefly Watch Project.

How to Find Fireflies

Fireflies love open areas near water and woods. They also gravitate toward darker areas with less light pollution, which is why it can be tough to find them in fragmented suburban yards or cities. Still, that doesn’t mean they aren’t there. If you live in a well-lit neighborhood and are striking out in the backyard, scout out your local or state parks. They’re usually dark enough at night to attract fireflies. If you’re still struggling to spot them, check the Firefly Watch Project map again and see if anybody in your area has reported a sighting.

Also, keep the calendar in mind. While firefly “season” varies significantly depending on geography, fireflies are most active in the spring and summer. In Minnesota, you can catch them from May to August, but in Florida and other warmer states, the season may last from March until November.

Equipment to Catch Fireflies

The equipment needed to catch fireflies is pretty basic: A butterfly net and a Mason jar or another transparent container with a moist, crumpled-up paper towel at the bottom. Obviously, you also need a lid for the jar or container that allows air to pass through but prevents fireflies from escaping. A piece of cut-to-fit cardboard with some tiny holes poked through it ⏤ or a trimmed down paper plate ⏤ affixed with duct tape works well. Store-bought “bug houses” are another easier alternative.

How to Catch Fireflies

Catching lightning bugs is straightforward: Find an open area free of tripping hazards and turn off all the lights. After your eyes acclimate to the dark, you should start to see them blink. Gently swipe at the firefly with a butterfly net until you catch it, and then carefully transfer it into the jar with your hand ⏤ or better yet, coax it in without actually touching it.

Now attach the cover, watch it blink, and snag some great photos. Be forewarned, though: Firefly photography can be tricky, so be sure to read up on it beforehand. Also, you don’t need to feed fireflies or give them standing water (insects can drown pretty easily). It may also be tempting, especially if the kids are asking, to keep the fireflies as pets but resist the urge. Fireflies don’t live that long, so keeping them for a day or two hurts their chances to breed and may cause stress-related mortality. After an hour or two of fun, let them go so they can go find a mate.

Note: Firefly populations everywhere are declining, but those on the western fringes of its ranges are in real trouble (think Arizona, Colorado, Nebraska), and every individual critter matters, so avoid catching them in such states.

Firefly Facts to Wow the Kids

Fireflies don’t really need help being more interesting — they are bugs that light up! — but the more you learn about them, the more fascinating they become. Here are a few fun facts to wow the family:

• Fireflies blink for the same reason that songbirds sing — to attract a mate; each firefly species has its own blinking pattern, and you can use that to identify the type you’ve spotted. One of the most well-known fireflies is The Big Dipper Firefly (Photinus pyralis), which has a prolonged, dipping flashing pattern.
• Fireflies also light up to let predators know that they’re toxic. While they aren’t a threat to you or your kids, to a potential predator, they could be deadly. In one odd case, a pet owner fed fireflies to his pet lizard, and it died.
• If you’re in the eastern US, all of the fireflies you find in the air will be males. The females blink back from the ground and usually don’t fly.
• Instead of the on-again, off-again flashing patterns that most of us are familiar with, synchronous fireflies put on a special show: male fireflies all blink at once, followed by the return signal from the females. Great Smoky Mountains National Park in North Carolina and Tennessee is famous for its annual spectacle of synchronous fireflies; tens of thousands of people flock there each year to see them.

Firefly Populations Are Declining

Because of the widespread use of insecticides (those mosquito foggers don’t just kill skeeters), habitat loss, and light pollution, fireflies populations are in trouble. To ensure that fireflies will be delighting folks for generations to come, we need to help them out. Here are a few tips:

• Avoid spraying insecticides, especially those that “fog” an area. Most foggers use broad-spectrum insecticides that kill everything they hit, including bumblebees and fireflies. It’s the insect equivalent of carpet bombing.
• Try to minimize your contribution to light pollution. Read up on the Dark-Sky Association for tips on how to minimize your light footprint.
• Finally, support groups and organizations that preserve habitat — especially wetlands and wooded areas — near you. In an age where land is increasingly parceled up and divided, preserved land is effectively a lifeline for a whole host of animals, plants, and insects, including fireflies.

Brett Ortler is a writer/editor, avid amateur entomologist, and all-around nature nerd. He’s the author of two popular insect books ⏤ The Fireflies Book and The Mosquito Book ⏤ and has edited over 300 other nature titles, including dozens of field guides on insects, the night sky, fish, and rocks and minerals.