Fireflies figure in summer memories

It’s tough to name an insect that is universally loved, but there is one that is near and dear to everyone’s heart: the firefly.

My July 4 column on fireflies drew dozens of comments and raised quite a few questions. All of the comments were in favor of these flashy insects, providing evidence that fireflies top the insect popularity charts. The questions showed that people are very curious about these summer strobe lights. Thus, here is “Fireflies: the Sequel.”

Several people asked me if fireflies are disappearing.

“It seems there used to be a lot more fireflies when I was young,” one man said. “I hardly see any nowadays. What happened to all of them?”

The answer to this question is not heartening, I’m sorry to say. There are not only anecdotal stories, there is hard and fast evidence that firefly populations are on a serious downslide worldwide. Some firefly populations have fallen by 70 percent in the past decade. They are, as one entomologist put it, “glowing, glowing, gone.”

What’s the cause of this decline? Round up the usual suspects: habitat destruction, habitat degradation and pesticides.

“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, destroying firefly habitat and natural prey,” explained researchers from Tufts University, sponsoring the website www.firefly.org.

“As their habitat disappears under housing and commercial developments, firefly numbers dwindle.”

Use of pesticides on lawns and fields can be lethal to fireflies as well.

A lesser-known factor in the matrix of habitat degradation is light pollution. Few people give thought to this issue, but our formerly dark nights are steadily giving way to nighttime “sky glow.”

Porch lights, yard lights, parking lot lights, and security lights all contribute to light pollution. Because fireflies communicate in “a language of light,” flashing an entomological Morse code to attract mates, defend territory and send warning signals to potential predators — darkness is a must. The more ambient light at night, the more difficult it is for fireflies to read each other’s signals.

One reader called to express concern about children catching fireflies. As naturalists, we always advocate using the utmost care if catching any animal for observation. We teach people that insect repellent on hands can harm insects, amphibians and most any small creature. Finally, we stress the importance of releasing the animal unharmed. This is especially important for fireflies, because adult fireflies have an important job to do and a short period of time in which to do it. They have to find mates and procreate in about two weeks’ time. Thus, if you do gently catch a firefly (without bug spray on your hands!) go ahead and marvel at it for a few minutes, then set it free to find its special someone.

Finally, the million-dollar question. A woman asked me, “What good are fireflies?” This is the quintessentially anthropocentric question, and I’ve heard it hundreds of times (just substitute any organism for the word “firefly”). Although the woman did not intend to be pejorative in asking the question, the implication is “What good does this creature do for me?”

There is an anthropocentric answer and an ecocentric answer. From an ecocentric point of view, fireflies are good just because — and humans are quite beside the point.

In anthropocentric terms, fireflies are good because they have scientific and economic value to humans. Fireflies provide important information for scientists seeking ways to increase energy efficiency in lighting. Bioluminescence, the creation of light with biochemicals, has broad implications and we’ve barely scratched the surface of the research in this area.

The economic benefit may come as a surprise, but in Malaysia and Thailand fireflies play a role in the tourism industry. Fireflies there are so awe-inspiring that there are special firefly tours, drawing people by the boatload to marvel at the beetles’ nocturnal light shows.

“Thousands of fireflies fill the branches of trees along the Mae Klong River (in Thailand),” reported Seth Mydans in The New York Times, “flashing on and off in unison — relentless and silent, two times a second, deep into the night.”

Biologist Sara Lewis of Tufts University described it as “one of the most amazing things you’ll ever see.”

Even before their role as a tourist attraction, fireflies provided other benefits to Thai communities. “Along the Mae Klong … the flashing trees were so thick along the riverbank that they served almost as highway beacons for boatmen in the night,” reported Mydans.

An elderly Thai woman reminisced about fireflies lighting the contours of the river so that people could navigate the canals at night.

“Fishermen worked in their nighttime glow,” Mydans relays from the people he talked with. “Before electricity arrived … villagers put fireflies in bottles to provide a dim light inside their mosquito nets — about as strong as the screen of a mobile phone.”

Thus, fireflies are “good” in many ways for humans. Regardless of philosophical viewpoints, many people I’ve talked to in the past few weeks agree that fireflies are part of the intangible quality-of-life that we enjoy here. Grandparents want their grandchildren to experience the same sense of joy among the dazzling little lights on warm summer evenings that they did 60-some-odd years ago. Parents have told me they’d rather have their kids chasing the glow of fireflies in the grass than downloading aps in the glow of an iPad.

And what do the kids feel about it? Well, watching their faces light up in wonder while a magical insect blinks in their carefully cupped hands says it all.

Here’s to summer evenings filled with a thousand points of light!

Ÿ Valerie Blaine is a naturalist with the Forest Preserve District of Kane County.

How to help the firefly

What can you do to curb the decline in firefly populations? Lots!

1. Turn your porch lights off.

2. Delay mowing your lawn for a little while until firefly mating season has passed.

3. Use fewer chemicals on your lawn.

4. Support the preservation and restoration of natural areas in forest preserves and park districts.

Courtesy of Valerie Blaine