Fireflies typically appear in Southwest Ohio in early June, but it can depend on the weather and temperature. I’m sure that Bill Felker of Poor Will’s Almanac has precise dates of the insect’s first appearance each season near Yellow Springs. I don’t have that, just a recollection of a now deleted text I sent to my daughter about seeing the first one of the season in early May, and how it seemed really early.
Lights around the world
There are nearly two dozen different species of fireflies in Ohio, with the common eastern firefly being the most likely to be seen in local backyards. Worldwide, there are an estimated 2000+ species of fireflies. Different species fly in different patterns and have variations in light color between green and amber. Some even blink their lights in a synchronized manner.
While I recall seeing them early in recent years, I have also thought that there seemed to be fewer of them. One year, the field next to our yard was noticeably less glowing than the preceding year.
It turns out I wasn’t alone, or imagining things, their numbers are declining. It’s a situation facing smaller creatures everywhere, with some familiar contributing factors: habitat and pesticides.
Where they live
Lightning bugs thrive (stop me if you’ve heard this before) in diverse edge habitats that offer woods, fields, and water. They lay eggs in rotten wood and decaying leaves. They need water. They prefer a variety of taller grasses. In other words, they like things messy. All of those things together get harder to find the more humans manipulate the environment into something that matches our visual expectations.
Out of sync
Pesticides almost certainly play a role in their current downward population trend. Broad spectrum pesticides sprayed at night to control mosquitos can impact them. According to www.firefly.org, no specific formal studies have been done on the potential effects of lawn chemicals on fireflies. However, on their website they reveal that, “two known studies indirectly suggest that these chemicals may be harmful to fireflies and larvae. Both show that lawn chemicals can have a serious detrimental effect on fireflies throughout all growth stages.”
And it stands to reason: because fireflies don’t cause any problems (they actually do a lot of good) there hasn’t been a specific reason to study their reaction to pesticides.
Additionally, their activity and success breeding can be disrupted by excessive lights and night traffic. Car headlights and flashlights have been shown to interrupt the sequence in their flashing before it is restored.
Lighting the way for more fireflies
If you want to see more fireflies, a perfectly manicured lawn is not the best route or place to look. In a contest between an old hay field by the creek and a golf course, the hay field will win every time. That’s not an option for most people. What most people can do are these four things:
- Leave some logs, branches and leaves where they lay.
- Mow less often. Fireflies spend their days on the ground. If you can, leave some areas unmowed or consider a native grass or prairie pocket habitat.
- Avoid the use of pesticides and lawn chemicals.
- Limit the use of lights in the summer to what’s necessary for personal safety.
More than a blinking light
- Because the larva are active predators, they are great for gardens, helping to control pests like slugs and snails for the 1-2 years they spend in that stage.
- Scientists are interested in the chemicals that create their Bioluminescence to better understand and treat cancer, among other things.
- Their glowing light doesn’t give off any heat, making it extra unique.
- They’re a great marker of a healthy and diverse habitat.
Fireflies are just another one of the amazing local creatures we have and possibly take for granted in Southwest Ohio. If you’re able, do what you can with the simple steps listed to help their survival. If you want to take a more active role, consider sharing your findings with research scientists through iNaturalist and Firefly Atlas.
Devin Meister is a local outdoors and wildlife enthusiast and has a blog called “Average Guy Outdoors.” He is an Ohio University graduate. Reach him at meister.devin@gmail.com.
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