Expert: Habitat destruction, pesticides lessening firefly population

Firefly season typically starts in March and peaks in June.

The firefly season has peaked and there is no sign that the population has seen a resurgence.

Firefly season typically starts in March and peaks in June, Texas firefly expert Ben Pfeiffer said. The firefly population across the state has been lessening because of factors like light pollution, pesticide use and habitat destruction.

Fireflies have two-year life cycles, so the way to tell if there has been a change in the population this year is to observe the population in the previous two years, Weatherford College Life Sciences Associate Professor Allison Stamatis said. Wet springs tend to lead to more fireflies in the next year, Stamatis said, but so far, she has not seen signs of a firefly resurgence.

Repairing spaces between a body of water and land is one example of habitat destruction, Pfeiffer said.

“It provides habitat for fireflies,” Pfeiffer said. “When you remove that corridor by say putting a home right on the body of water and cutting down all the trees and putting in a big lawn, then you’re removing the habitat for fireflies.”

Stamatis said light pollution can also lead to lessening populations of fireflies because the male fireflies use light signals to attract females and reproduce. This can even be the case in suburban and rural areas when homeowners leave house lights on all night.

“Even in more rural areas, that’s potentially decreasing the habitat for fireflies,” Stamatis said.

Pfeiffer and Stamatis said broad pesticides can kill many insects, including fireflies and their food source. Stamatis recommended that people who want to create a firefly habitat in their backyards use pesticides to target certain insects specifically.

“When you use just a broad spectrum pesticide, it kills all the good stuff in addition to the bad stuff,” Stamatis said. “If you have pests that you’re trying to treat, treat the specific pest.”

Pfeiffer recommended that homeowners foster more natural areas in their yards.

“You’d be surprised in how many habitats I visit that the fireflies are being supported by little bitty areas that are just left to go natural and have a really deep soil matter because the homeowner or the landowner doesn’t rake the leaves there or clean the area necessarily, they kind of let the soil build,” Pfeiffer said. “That attracts snails and worms and slugs, and that is food for baby fireflies, essentially, firefly larvae. So, you have to have a balance of all this stuff in order to keep fireflies.”

Firefly species in Parker County tend to be the common type, photinus pyralis, Pfieffer said. Smaller species are also present like photinus granulatus and photinus dimissus, which are referred to as lawn fireflies and also exist in Oklahoma. The photuris species, which eats other fireflies, is also present in Parker County.

Species of fireflies tend to be unique to certain areas, Pfeiffer said.

“What’s going to occur in Weatherford is going to be different than what’s going to occur maybe in Brownwood,” Pfeiffer said.

Places near water are good for seeing fireflies, such as near the Brazos River, because fireflies tend to build habitats near water, Pfeiffer said.

Edges of wooded areas that open to fields can also be good places for firefly sightings, Stamatis said, as well as creek beds that have dried in the summer.

“It has a little bit of open space where they can be seen by a mate, but the wooded area provides more shelter and that’s where it kind of holds on to more of the water, giving them that moist habitat,” Stamatis said.

Stamatis said it is fine to catch fireflies in jars as long as they are released.

“That’s why I love to teach — sometimes when you catch them for a short period of time, you can teach other people about them, and they respect them more,” Stamatis said. “They may do something to help their habitat.”

Sometimes industrialization can wipe out species of fireflies that are native to a certain area, which is what happened in Japan and Houston, Pfieffer said.

“A lot of these outlying communities like Weatherford can do work to cherish their populations of fireflies because they’re not Fort Worth yet, or they’re not Houston yet,” Pfeiffer said.