Eco Tip: Love Fireflies? Dim the Lights To Help Them Thrive

Marsha Low, Weavers Way Environment Committee

For me, watching the fireflies come out is one of the great pleasures of summer evenings. As the dark deepens, the light show they put on is truly a thing of wonder. But you may have noticed fewer fireflies around these days, as their numbers are on the decline due to habitat loss, light pollution, and the use of chemicals in the landscape.

Fireflies use their bioluminescence to help attract mates. Human light pollution interferes with their flash patterns, upsetting their mating rituals and leading to a decline in their numbers, so consider reducing your use of outdoor lighting. If you’re concerned about security, you can install motion-activated lights, which only turn on when triggered by someone or something coming within the range of the light fixture and then switch off after a few minutes.

Another reason for the decline of fireflies is the use of chemicals on lawns and gardens. Fireflies spend most of their lives as ground-dwelling larvae, so insecticides designed for grubs will kill them. To help, keep undisturbed areas of leaf litter and wood debris in corners of the yard, and don’t mow the lawn too often or too short in early summer. And if you use chemicals in your landscape, consider ending the practice. There are so many reasons why going organic is better for you and the environment, and helping fireflies is just one more!