A Spark in the Park: Lightning Bugs

 Growing up in western Montana, the only exposure a kid gets to fireflies is anecdotal, like the bug in Sam And The Firefly from the Dr Seuss series of books; a tiny comic superhero. Moving to Missouri and camping on the Huzzah River, watching the early evening light display of real-life fireflies was memorable. 

Sometimes parents wonder where their children’s boundless energy comes from. A compelling question for the know-it-all biochemist, who will tell you “adenosine triphosphate,” or ATP, is the molecule responsible for capturing and transferring the energy of metabolism into muscular and nervous activity. 


ATP is something all living creatures have in common; even the ones whose movements are few, like the three-toed sloth, or nearly undetectable, like the sea sponge. Animals, plants, bacteria, algae – they all run on ATP. 

Sigma Millipore of St Louis began its existence as Midwest Consultants. It was founded in 1935 by the Fischer brothers, Aaron and Bernard, who were essentially salesmen. After World War II, chemical engineers Leo Bressler, Walter Stern and Sol Kesslinger joined the small company, and focused their efforts on the manufacture of saccharin, a nasty sweetener that grew popular due to the wartime rationing of sugar. It was a spartan lab process at best. 

Monsanto entered the saccharin production business and squeezed the tiny firm out. Midwest turned its efforts toward other synthetic products, including inks and shoe polish. Dan Broida, a key manager at Midwest, persuaded Lou Berger, a young biochemist from Washington University, to join the firm. Berger, who had studied under local Nobel Prize winners Carl and Gerty Cori, brought his research on ATP with him. 

Sigma Chemical became the first manufacturer to produce pure ATP for science, and it proved to be a financial boon for the company. The enterprise was renamed Sigma Chemical in 1946, and the production of ATP became its sole focus.

In its attempts to capitalize on ATP, Sigma went on to investigate reactions involving the molecule. This brought them to the firefly, aka lightning bug. 

The firefly’s tail, as most Midwesterners will tell you, generates light. It contains a chemical called luciferin. In the presence of ATP and an enzyme called luciferase, it generates a cool fixed wavelength yellow green light. Because it’s both a “light on, light off” indicator of life, and the strength of its glow is proportional to the amount of life present, the reaction between luciferin and ATP proved to be a great tool for things like determining contamination of foods, and disease progression. Applied in 1987 to dust from Mars, the results were inconclusive as to whether there was demonstrable life there, but kids from the Sigma Firefly Club were thrilled by the test.  

From 1960 through the mid-1990s, the Sigma Firefly Club incentivized the collection of fireflies in 25 states. it recruited children, mostly, to catch and send fireflies to St Louis, in return for tee shirts, collection nets, and hard cash. In its first year, it offered premiums including a bicycle and tickets to the Forest Park Highlands, Holiday Hill, and Chain Of Rocks.  During its heyday, the club accounted for more than 3 million fireflies per year. Sigma provided canisters for collection, and when full, kids would ship them off. It was relatively good money for the time – starting wage was $0.50 per hundred, but if you reached 20,000, you achieved one cent per bug. Sigma would then send back checks made out to the kids, with the club logo stamped on the checks. 

Some firefly collections became a civic endeavor. The Allison Firefly Club in Iowa brought in enough fireflies over five years to build a community pool. A preteen in Vinton, Iowa rented nets and hired kids to work for him at a lower rate than Sigma paid, making a nice profit as he got past the 20,000 mark. A grown up resident in the same town enlisted 400 kids over a 45 mile radius, and also employed a pickup truck with a trawling net. She told the Chicago Tribune in 1987 that she averaged about 35,000 every other day, and bussed them to St Louis every summer for 25 years. As a result, she was able to put her kids through college.

It was estimated that in the course of its existence, the Sigma Firefly Club harvested about 100 million lightning bugs. A number of these probably came from the Lafayette Park neighborhood, a short 15 minute bike ride from Sigma headquarters on DeKalb Street.

Sigma Chemical was sold to Merck in 2014 for $17 billion, and today luciferase is just a bit actor on their stage. The molecule itself was synthesized in 1985, and that chemistry is more scalable than recruiting more kids. You can, however, still buy whole desiccated fireflies from the Sigma catalog – perhaps from the remainder of an earlier oversupply. 

Firefly behavior:

A firefly is actually a beetle with a two month life span, and its larvae eat slugs, worms and  snails, all of which are less magical to stare at on a summer evening.

The adult stage of the firefly is so short that, outside of a bit of pollen or nectar, they might not eat at all. The larvae also emit light, and, as a lot of kids who make personal decor of the tails will tell you, the tail without the rest of the beetle serves nicely as a ring light. 

It’s easier to see and catch male fireflies, as they fly more than females, who tend to stay near the ground. As you might surmise, the glow is intended to generate mating interest between individuals. 

The optimal time to see and catch them is at dusk. As night progresses, the males fly higher in the sky.

Light pollution has a definite negative impact on the ability of fireflies to hook up. They also respond poorly to many lawn chemicals. They are at their best around Lafayette Square in the moist fields and trees of Lafayette Park in early to late June, away from the bright lights of Park Avenue. Fireflies are generally threatened as a species in urban areas, harvested to extinction, poisoned, or deprived of habitat in many spots. Interestingly, once gone from an area, they don’t generally migrate back. 

My wife and I walked through Lafayette Park after a rain on June 21, and were delighted by the light show around 8:30pm. Lightning bugs are easy to ignore, but try to remember your reaction to seeing them as a child. You might recapture the magic of a thousand real points of light. We’re fortunate to have them, and it’s a great season in a wet year, so enjoy the show!

Note: On June 28, from 7-9:30 pm, the Missouri Botanical Garden is hosting “Fireflies After Dark”, a strolling appreciation including appetizers from Sugarfire Smokehouse and a variety of drinks. You’ll learn a lot about what makes them tick…or twinkle. Here’s a link to register:


Thanks to research sources, including:

The always whimsical Bill McClellan of the St Louis Post-Dispatch, for his short history of Sigma Chemical; Humble Beginnings For A Great Company; October 3, 2014.

UPI; The Business End Of Fireflies; Elizabeth Pennisi; June 4, 1988.

Firefly Conservation and Research; firefly.org; How To Help; https://www.firefly.org/how-you-can-help.html

A fascinating site for research into arcane topics is the Atlas Obscura online. Try their feature entitled, For Decades, The Ultimate Midwestern Summer Job Was Headhunting Fireflies; Cara Giaimo; August 3, 2016.This is Sigma misnomer, as the young jobbers were actually tailhunting, but still a good read. https://www.atlasobscura.com/articles/for-decades-the-ultimate-midwestern-summer-job-was-headhunting-fireflies

Pennies From Heaven For Firefly Catchers; UPI via the Chicago Tribune; August 24, 1987

Silent Sparks – The Wondrous World Of Fireflies; Sara Lewis; Princeton University Press; 2016

Fireflyer Companion; Vol 1; Number 1; Winter 1993-94. University of Florida Dept of Entomology; Gainsville FL; http://entnemdept.ufl.edu/lloyd/firefly/ffcomp1-1.pdf. A lot of information, both folklore and science; with a firefly crossword puzzle! 

Sigma-Aldrich website for corporate history; https://www.sigmaaldrich.com/life-science/sigma-life-science/sigma-history.html