6 Ways to Help Fireflies

Are Firefly Populations in Decline?

Firefly populations seem to be dwindling worldwide. Scientists attending an international conference on firefly conservation in 2008 shared alarming data. In one area of Thailand, firefly numbers dropped 70% in just 3 years. Ask anyone who's been around a few decades whether they see as many fireflies now as they did when they were kids, and without exception the answer is no.

Fireflies are sensitive to habitat disturbances. Fireflies need meadows and streamsides, not cul-de-sac developments of manicured lawns and well-lit landscapes. But all is not lost! Here are 6 ways you can help fireflies.

Don't Use Chemical Fertilizers on Your Lawn or in Your Garden

We see fireflies as adults, flashing signals to each other across our backyards. Most people don't realize that firefly eggs and larvae live in the soil, just below the surface. Chemical fertilizers add salts to the soil, and those salts can be deadly for developing firefly eggs and larvae. Even worse, firefly larvae feed on soil-dwelling organisms like slugs and worms. Just think – the worms eat the chemical-laden soil, and the firefly larvae eat the worms. That can't be good for fireflies.

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Minimize Your Use of Pesticides

Fireflies are insects, after all, and any broad-spectrum pesticides you use can impact them adversely.  Whenever possible, use horticultural oils or soaps, which can only harm fireflies if you happen to spray a firefly directly with the product. Choose pesticides that treat specific pest problems, like Bt, a naturally-occurring bacteria that can be used to treat caterpillar pests.

Keep Lawn Mowing to a Minimum

Enough with the perfectly manicured lawn! Although you might not see them, fireflies spend the day resting among the blades of grass. The more you mow, the less inviting your lawn is for fireflies. If you have the space, consider letting an area of your lawn grow long. You'd be surprised what a little meadow can do for wildlife, especially fireflies. 

Add Trees and Shrubs to Your Landscape, and Leave Some Leaves on The Ground

Homes in newer developments seem to be surrounded by lots of lawn, dotted with a few evergreen shrubs and a tree or two, and entirely devoid of leaf litter.  Fireflies need places to hide and perch, and require a moist habitat. Firefly larvae feed on slugs, snails, worms, and other critters that like it damp. Leave some leaf litter or other garden debris on the ground, which will keep the soil beneath it damp and dark. Plant an area with trees and shrubs to give adult fireflies a place to perch.

Turn Off Outdoor Lights During Firefly Season

Scientists suspect that artificial lighting may interfere with firefly mating. Fireflies flash to attract and locate mates. Porch lights, landscape lighting, and even street lights can make it difficult for fireflies to find each other. Fireflies are most active from dusk to midnight, so at the very least, minimize your use of outdoor lights during that time period. Consider using motion-activated lights (you'll save energy, too!). Use landscape lighting that is low to the ground, and direct the light straight up or down rather than broadcasting light across your yard.

Install a Water Feature

Most fireflies live along streamsides or marshes, and prefer an environment with standing water. If you can, install a pond or stream feature in your yard. Again, firefly larvae feed on moisture-loving creatures like snails. If you can't add a full water feature, keep an area of your yard well-watered, or create a small depression that will stay moist.