How to Catch Fireflies


Most of us have fond memories of catching fireflies or lightning bugs on warm summer nights. Many people kept them in jars—sometimes a jar full of fireflies can produce enough light to read by. If you want to catch fireflies, here are a few tips that will help you along.

Where to Look

Fireflies are easy to spot—just look for the flashing lights. They typically love long grasses, marshy areas and regions near the edges of ponds, lakes, streams and other bodies of water. They can thrive under low-hanging trees, in forests and fields, and even in your yard or vegetable garden.

Watch Your Light

Fireflies communicate using their flashing lights. If you want to catch one, you have to act like one. First, turn off your exterior house lights—these may confuse fireflies and make them less likely to respond to light signals from other fireflies. Then take a flashlight outside.

If you are having trouble getting near the fireflies in your yard, imitate one of them by shining your flashlight directly up and down, or by repeating the light patterns you see fireflies emitting. This may or may not work; many scientists who study fireflies have better luck with LED lights than with battery-powered flashlights. Never shine a light directly at a firefly; it’s likely to scare them away rather than attracting them.

In addition, you may have better luck catching fireflies if you place a blue plastic disc or piece of paper over your flashlight to turn the light blue. Scientists believe fireflies don’t interpret blue light the same way they see other colors, so the light won’t disorient their flash patterns.

Catch Carefully

When you get close enough, catch your fireflies using a net. Place the fireflies you catch into a clear jar with a lid that’s been pierced to let in air. You should also place a moistened paper towel or preferably a damp unbleached coffee filter inside to keep the air in the jar humid. This way, your fireflies will have air to breathe and won’t dry out. Be sure to crumple your damp paper towel or coffee filter to create areas for the fireflies to hide. Change out paper every 2-3 days, or as needed. This is important to keep bacteria and mold from growing on the damp paper.

How to Keep Alive

If you would like to keep your fireflies alive the longest, use apple slices in your jar. Fireflies will readily drink the juice from a fresh apple. You can also use grapes, raspberries or other available fruit. These fruits however will rot a lot quicker. Additionally, if you have a mister (small or large bottle), use this with distilled water and give the jar a misting occasionally. This is to help keep the environment moist but also simulate the natural environment better. The inside of homes are often very dry and not ideal conditions for firefly survival. Occasional misting keeps them from drying out too quick.

Work In Pairs

It’s often more effective to work in pairs when catching fireflies, with one person to hold the jar and another to use the net. Be sure to use care when catching them; fireflies can be fragile.

Let Them Go

Once you have a jar of fireflies, don’t keep them for longer than a day or two. Let them go, preferably at night because that’s when they’re most active and able to avoid predators. If you keep them for longer, the fireflies are likely to die.

Some people remember crushing fireflies in their fingers to make their hands glow and keeping them in unventilated jars for several days. While this might not have caused serious damage to firefly populations in times when they were more plentiful, today’s firefly numbers are dwindling—so each one matters. Catch fireflies carefully, treat them gently and release them into the wild again when you’re done, and you’ll be able to enjoy these fascinating creatures without causing any harm.