Bye-Bye, Fireflies?

JUL 14

When we think of our favorite signs of summer, surely fireflies are at the top of the list. Many of us have memories of spotting and catching them as they light up a warm summer evening. But some scientists suggest that our children may not have the same firefly memories we had. The firefly population is on the decline; they are disappearing from fields, forests, and our back yards across the globe.

What could possibly account for the dwindling fireflies? According to the writers at, no one knows for sure. Possible culprits are increased development and light pollution. Because fireflies thrive in warm, humid conditions with plenty of forest litter near standing water, ongoing land and water development is rapidly encroaching upon key firefly habitats. Fireflies don't migrate. Once their habitat is destroyed by logging, construction, water pollution and boat traffic, firefly populations will begin to fade away.

Another uphill battle that fireflies face is light pollution. When I was a kid, I thought fireflies used their lights to see where they were going at night. Naturally, I assumed turning on more houselights would be a welcome aid for these little guys. Turns out it is quite the opposite! Fireflies use their lights to communicate with each other and other night-time critters. Speaking a language of light requires careful synchronization. Interruptions from other light sources such as vehicle headlights, streetlights and lights from homes and stores throw off firefly flash patterns. If fireflies have difficulty signaling to each other during mating times, fewer firefly larvae are born next year.

So what can we do to keep our summer nights sparkling with fireflies? Scientists have not studied this issue long enough to be certain, but there are some common sense practices that will be beneficial to the firefly community (and the environment at large). We might not be able to do much about land and water development, but we can make our own yards a refuge for fireflies. Try turning off those outdoor lights, or leave them on only when you need them. Security around the home is important but if you aren't using outdoor lights throughout the entire night, turn them off. Let logs and forest litter be. Firefly larvae grow up in rotten logs beneath the forest canopy. Plant trees in your yard and consider leaving natural litter around them and if your yard is in or near the woods, let logs and branches accumulate in certain areas. Don't over-mow your lawn. During the day fireflies stay on the ground, so frequent or low mowing will disturb them. Fireflies require standing water to thrive; try creating water features in your yard to encourage fireflies to congregate. Avoiding pesticides and using natural fertilizers can also be helpful in making your yard a healthy spot for fireflies. Lastly, there is always strength in numbers. If your neighbors adopt some of these practices, your neighborhood might see an increased firefly population.

If fireflies continue to fade, our summer nights will be a little darker and a lot less magical. But it is not too late to turn the decline around. Being aware of the problem is one big step and positive action is another. Environmentally conscientious practices can help keep our summer skies sparkling; because no one wants it to be lights out for fireflies.