We celebrated Fourth of July with fireworks that were loud and spectacular.

Nature produces a quiet summer spectacle in the light show of fireflies.

Fireflies don’t bite, sting, pinch, carry disease or even fly very fast.

They are also known as lightning bugs, glowworms or fireflies, but they are not bugs, flies or worms; they are beetles in the family Lampyridae.

The firefly species Photuris pensylvanica, commonly called the Pennsylvania firefly, is the official state insect.

There are about 2,000 known species around the world.

North American species number about 170, with about 33 species known in Pennsylvania.

Lightning bugs prefer moist and humid areas for egg and larval development, so weather conditions and soil moisture will affect their numbers from year to year.

They thrive in forests, fields and wetlands near lakes, streams and rivers.

The females lay eggs in moist soil, and the larvae that emerge, sowbug-like in appearance, are voracious predators of slugs, snails and earthworms.

Eggs and larvae of some species also glow, hence the name “glowworm.”

The larvae live in soil and leaf litter for one to two years and feed by injecting paralyzing digestive juices into their prey and then sucking out the body contents.

In spring, they pupate in small mud balls and then emerge as adults in early summer.

The adults live for only a few weeks and die after mating.

During their short lives, adults feed on nectar or pollen or don’t eat at all.

The bioluminescence produced by fireflies is cold light.

It is almost 100 percent light, creating virtually no heat.

The light is generated in organs on the abdomen of fireflies by two rare chemicals: luciferin and luciferase.

Together with oxygen and a body chemical called adenosine triphosphate, the chemicals are converted into energy.

The “taillights” are flashed on and off by fireflies to attract mates.

They are also used to signal danger or a warning.

During the day, adult fireflies rest on plants near the ground.

At dusk, the males start flying upward and flashing, looking for responsive females, who perch, waiting, on grass or leaves.

Most of the fireflies you see flying are males.

Each species of firefly has a unique flashing pattern called “flash trails” used by the males.

Females respond with a single flash only, which is timed to a precise interval to correspond to the flash of an appropriate mate.

In recent years, people in many areas have noticed a decline in the number of fireflies observed on summer evenings.

Although researchers lack long-term data to confirm population declines, it is not difficult to identify certain human-related activities as possible culprits.

From the 1950s to the 1970s, huge numbers of fireflies were harvested from the wild for their luciferase, which was used in medical research.

Loss of firefly habitat because of land development and draining of wet areas has also contributed.

Light pollution is a factor because it can disrupt the light-dependent mating behavior of many fireflies.

Fireflies also face threats from pesticide usage and climate change.

A few things that you can do to help fireflies include: turning off outdoor lighting during evening hours, reducing pesticide use in the garden, mowing grass to a height of three to four inches, and in autumn, leaving fallen leaves on the ground in your landscape.

Leaf litter provides shelter for glowworms and other beneficial insects.

Whether you know them as lightning bugs or fireflies, they are amazing.

“Growing Green” is contributed by Lehigh County Extension Office Staff and Master Gardeners. Information: Lehigh County Extension Office, 610-391-9840; Northampton County Extension Office, 610-813-6613