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Naturally speaking: Fireflies add shine to the summer night

The sun set just a half hour ago as you casually sit in your backyard enjoying the summer skies and then look about at the flashes of light that pop above your lawn. Fireflies, aka lightning bugs, make their evening debut to provide you with a spectacular visual performance.

Pennsylvania designated the firefly, Photuris pennsylvanica, as the official state insect in 1974. A small, unremarkable beetle by day, fireflies can transform a midsummer night into a fairyland of tiny, brilliant twinkling lights — a true wonder of nature.

There is a story about how this bug became our state insect. It began when elementary students in Upper Darby, Delaware County, saw an article about Maryland adopting a state insect.

Pennsylvania lacked a state insect at the time, so the students entered the firefly to be selected as the insect symbol to the General Assembly.

On April 10, 1974, the firefly was formally adopted by the Pennsylvania General Assembly. Commonly called “lightning bug” in Pennsylvania, it produces light through an efficient chemical reaction using special organs, with very little heat given off as wasted energy.

Fireflies use species-specific flash patterns to attract members of the opposite sex (though not all firefly species are bio-luminescent as adults). These flashing signals range from a continuous glow to discrete single flashes to “flash-trains” that are composed of multi-pulsed flashes.

In most North American fireflies (including Photuris pennsylvanica), the males fly about flashing their species-specific flash pattern, while females are typically perched on vegetation near the ground.  When a flashing male attracts a female, she responds at a fixed time delay after the male’s last flash.  A short flash dialogue may ensue between the fireflies as the male firefly locates her position and descends to mate.

The light produced by the firefly is the most efficient ever made.  Almost 100% of the energy in the chemical reaction is emitted as light. In comparison, an old-fashioned incandescent light bulb only emits 10% of its energy as light while the other 90% is lost as heat. Researchers are studying how to create an even more energy-efficient light bulb.

If you’re seeing fewer fireflies each summer, you’re not alone. Anecdotal evidence suggests firefly populations may be on the decline, most likely due to a combination of light pollution, pesticide use and habitat destruction. For example, according to, if a field where fireflies live is paved over, the fireflies don’t migrate to another field, they just disappear forever.

You can help our state insect make a comeback by considering these choices.

Skip the chemicals: Most chemicals used outdoors to kill or deter certain bugs aren’t that selective; they will likely kill or deter fireflies as well. And since larvae, often called “glowworms,” are born underground, lawn chemicals in the soil will be detrimental as well.

Don’t disrupt the slimy things: As magical as fireflies may be, the larvae have a less-than-enchanting secret; they’re wee carnivores that feast on worms, grubs, slugs and snails. (And they do so by immobilizing their prey with toxic enzymes before sucking out the liquefied body contents. Sweet!) To keep the zombie bug babies happy so that they can grow up to become pretty fireflies, leave their slimy victims alone.

Provide good cover: During the day, nocturnal adult fireflies hide in the grass and low-profile plants. A nice variety of shrubs, high grass and low-growing plants will provide shelter.

Give them what they like: Fireflies like moist areas, especially wet meadows, forest edges, farm fields, and wild bog, marsh, stream and lake edges With 2,000 species of fireflies — and many of them having different diets — it may be hard to pinpoint what your local variety likes to eat. Many adult fireflies eat very little, but regardless, many eat a variety of pollen and nectar, so having a lot of flowers around should prove enticing.

Dim the light: Since fireflies are so reliant on their “fire,” confusing them with artificial light can cause many problems. Street lamps, garden lights and porch lights can all make fireflies a little shy.

Don’t put them in a jar: Yes, it may be one of the joys of childhood, but collecting fireflies in a container can lead to accidental death — not to mention bug trauma. Instead, enjoy them as they flit about freely.

Fireflies have always captivated people of all ages.  For most, they bring out happy memories of childhood curiosity and wonder.  Many poets have expressed their love of this insect.  Here is one that will top off this column like a cherry on top of a sundae.

“Lightning Bugs” by Ernest Slyman

In my backyard,
They burn peepholes in the night
And take snapshots of my house.

Source: Berkshire mont

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