Like Fourth-of-July fireworks, cool swims on hot days, and lazy vacations,
fireflies are a sign of summer. Many of us have cherished memories of
spotting and catching them during warm summer evenings and running through
fields that sparkled as if strewn with stars. But there are signs our
kids may not grow up with the same firefly memories we had. That’s because
fireflies are disappearing from marshes, fields and forests all over the
country—and all over the world. And if it continues, fireflies may fade
forever, leaving our summer nights a little darker and less magical.
Why Are Fireflies Disappearing?
Nobody knows for sure. But most researchers blame two main factors: development
and light pollution.
Most species of fireflies thrive as larvae in rotting wood and forest
litter at the margins of ponds and streams. And as they grow, they more
or less stay where they were born. Some species are more aquatic than
others, and a few are found in more arid areas—but most are found in fields,
forests and marshes. Their environment of choice is warm, humid and near
standing water of some kind—ponds, streams and rivers, or even shallow
depressions that retain water longer than the surrounding ground.
The problem is that in America and throughout the world, our open fields
and forests are being paved over, and our waterways are seeing more development
and noisy boat traffic. As their habitat disappears under housing and
commercial developments, firefly numbers dwindle. Logging, pollution and
increased use of pesticides may also contribute to destroying firefly
habitat and natural prey.
Human traffic is believed to disrupt firefly habitat as well. While scientific
studies have only been done for the past few years, there’s plenty of
anecdotal evidence in areas that were once full of fireflies—and much
of it goes back generations. Some areas once had so many fireflies that
they profited from running firefly tours in marshes and forests—but since
human traffic has increased, firefly populations have gone down.
Too Much Light At Night
Scientists don’t know enough about fireflies to tell for sure. But the
signs are indicating light pollution as a major factor in the disappearance
of fireflies all over the world.
Both male and female fireflies use their flashing lights to communicate.
Some species synchronize their flashes, sometimes across large groups
of thousands of insects. All species speak a language of light—scientists
believe they use it to attract mates, defend their territory, and warn
Human light pollution is believed to interrupt firefly flash patterns.
Scientists have observed that synchronous fireflies get out of synch for
a few minutes after a car’s headlights pass. Light from homes, cars, stores,
and streetlights may all make it difficult for fireflies to signal each
other during mating—meaning fewer firefly larvae are born next season.
Where fireflies once had uninterrupted forests and fields to live and
mate, homes with landscaped lawns and lots of exterior lights are taking
over. The reduction of habitat and the increase in lighting at night may
all be contributing to make fireflies more rare.
Fireflies are fascinating creatures that light up our nights and bring
a sense of magic and mystery to our environment. If they disappear, it
will be a great loss to habitats and generations of people all over the