The Science of Fireflies

During summer nights, something magical happens. Tiny insects light up the night sky, making summertime just a bit more special than it already is. If you’re like me, you can’t help but associate summer with fireflies. Many people know and love fireflies, or depending on who you ask, lightning bugs. I still remember catching them in mason jars as a kid, and nothing was as fascinating as those little bugs. 

Despite their name, fireflies aren’t flies, they are beetles! They’re harmless and feed on smaller insects, slugs, and worms. The number one question people have about fireflies is how and why do they light up? The light is created by a chemical reaction that occurs called bioluminescence, allowing them to convert energy into light. Their flashing light is often known as cold light, as it produces little to no heat.  

Just like with any insect, there are many different species of fireflies. Each species has their own unique flashing pattern. When an adult firefly lights up, it’s primarily used to communicate to other bugs of the same species that it’s ready to mate. Males flash their signal to females that respond with a specific pattern in return. It’s basically them saying, “Hey, we’re the same species!!” All larva fireflies can light up and use their lights to ward off predators. 

If you want to attract these magical insects to your yard, here are three things you can do: 

1. Reduce or eliminate using chemicals on your lawn. 
2. Turn off or eliminate any extra lighting you may have on your property. The light may interfere with the fireflies’ ability to communicate with one another!
3. Plant low, overhanging trees or tall grass in your lawn. This provides a space for them to rest and stay cool during the day before night comes around. 

For more info on common insects in your lawn and how to control them, check out Publication 2331, “Control of Insects Pests in and around the Home Lawn.”