Something’s Aglow at the Paonia River Park

By: Noah Steinburg, WSCC Intern

Fireflies are being discovered all over Colorado, and now we’ve even had some sightings in our very own Paonia River Park. What’s changed, and how do we keep these marvelous insects from leaving again? Let’s dive into it.

First, a quick background.  Fireflies, or lightning bugs depending on where you’re from, are a type of beetle that glow, or at least that’s the kind we think of. The truth of the matter is several species of fireflies don’t glow. Fireflies use the glow to find mates while non-glowing species rely on pheromones. It’s entirely possible that these non-glowing species have been in the area for much longer than anyone would’ve thought. 

In Colorado, we get a few different species of fireflies. The first is called the Photuris sp., which in English translates to light terror due to the behavior of using their lights to lure and eat males of other species. There’s Ellychnia flavicollis or yellow necked firefly which is found in Baca county. The Photinus pyralis or Common eastern firefly, is most likely the species we’re seeing here in Delta County. It can also be found in Baca County. The Ellychnia corrusca complex is an interesting species, as it’s actually believed to be several different species all grouped together. They can be found all over, in places like Boulder, Larimer, Weld, Douglas, Jefferson, Yuma, Jackson, Sagauche, Mesa, and Conejos counties. Pyropyga minuta, or the flower elf, is a special kind of firefly as they’re active during the day. You can find them in Larimer, Otero, Sedgwick, Prowers, Huerfano, Denver, Baca, Gilpin, Kiowa, and Arapahoe counties. 

Now fireflies have been spotted in the Paonia River Park, and some people may be asking why? The first thing we need to look at are the requirements they’d need to survive. Fireflies need to live in moist wet areas with a good amount of leaves and bugs on the ground for their larvae to survive. The River Park has all these things, with shaded areas where people aren’t meant to walk being the perfect area for the larvae to thrive, and an increase in rainfall this season which has created the perfect environment for fireflies. 

Fireflies at the River Park [Click here to view the fireflies in the Park in action! Credit: Anne Lee Foster] 

Like most insects, fireflies have a larval phase. These emerge during spring and early summer, when they’re most vulnerable. They live in the topsoil which is composed of fallen leaves, bark, and other organic waste. As larvae, fireflies are at risk of being crushed by animals, or more commonly, people. Firefly larvae are mostly carnivorous, sustaining themselves by eating invertebrates like snails and slugs. Because pesticides are commonly used to treat snails and slugs in lawns,  fireflies may be hit twice as hard by pesticide applications, which not only kill firefly larvae and adults, but their food source as well. One solution? Let the fireflies provide natural pest control. The more fireflies come back, the more larvae will be made, and because of this, those larvae will be able to act as a natural pesticide.

Besides pesticides, fireflies also face a disadvantage when it comes to light pollution. In brightly lit places the males and females won’t be able to see each other’s glowing. Humans of course are the cause of light pollution and yet the solution is simple: be mindful of your lights, specifically ones you may have set up in your yards. Remembering to turn lights off when they’re not needed is key to not only keeping the light pollution down, but it keeps the electricity bill lower as well. Reducing light pollution helps many other species as well.

Outside of pollution, pesticides and habitat loss, they  have one more unique threat: over-collection. While fireflies are truly beautiful, and catching them in jars is an activity that many people enjoy, we must remember that they aren’t meant to be captured. Dying in captivity is a big threat that fireflies face, so just be mindful!

We all have the ability to help in small ways to ensure fireflies will come and stay in our community. Every small thing will add up into a big change.