BRATTLEBORO—When was the last time you stopped to watch the small sparks of light from fireflies pricking the summer darkness?
For many people, fireflies evoke little moments of wonder, awe, and curiosity and added a sprinkle of magic to their childhood.
Last year, one of those people, Jane Wheeler of Brattleboro, a volunteer with Firefly Watch, started her observations around June 16.
The Mass Audubon program collects data from Wheeler and other citizen scientists across North America. Each volunteer spends approximately 10 minutes a week observing fireflies in one location.
This summer will mark Wheeler’s third year participating in the project, which she learned about while “just playing around” on the town’s website, Brattleboro.org. There she found the activity listed on the page devoted to “Living and Learning.”
“It’s really easy,” she said. “The form is pretty easy, and the website has all the information you need to know.”
For each entry, along with filling in the date and habitat type, Wheeler also makes note of the weather and temperature. She looks up the wind speed and temperature online before heading outside, usually between 9:15 and 10:30 p.m.
To conduct the count, she stands in one place and holds three, 10-second observations. She counts how many flashes she sees in those respective intervals. She also pays attention to the flash patterns.
Wheeler conducts the observation every night during the week and then inputs her data on Friday or Saturday.
“I find it is more useful to go out every night because things change,” she said.
Local insects, local environment
Understanding fireflies is about understanding your own backyard, its environment, and its health, said Dr. Sara Lewis, a professor of biology at Tufts University and author of Silent Sparks: The Wondrous World of Fireflies.
Lewis said that, as a child, fireflies sparked a sense of wonder that carried her into a career.
The study of these insects is “a really local question because fireflies are really local, they don’t get around much,” Lewis said. “But it’s really great to focus your attention. You can see so much more when you focus your attention.”
Lewis leads the team of researchers working with Firefly Watch. Scientists are using the data to track the geographic distribution of fireflies and learn how environmental factors impact them.
To join the effort, volunteers create an account at massaudubon.org/get-involved/citizen-science/firefly-watch. The website outlines how to pick a location, how to make observations, and how to identify “flash patterns,” or the series of blinks unique to each firefly species.
Lewis became involved with the effort to collect firefly data several years ago.
While attending a firefly conference in Thailand in 2008, she had a conversation with a reporter from the Associated Press who wanted to write a piece on how firefly populations were declining around the world.
In Lewis’s opinion, not enough data exist to draw such a conclusion — and from this conversation grew the idea to organize citizens to help gather data, she said.
Scientists have good data on certain species — mostly in the United States — but have little to no data on others, she said.
For example, one species that is thriving is “the Big Dipper firefly” named for its J-shaped flash pattern. This “habitat generalist” loves any open area — from a field to a parking lot to a golf course to the streets of Brooklyn.
Dr. Adam South, a former graduate student who worked with Lewis, helped launch the project, she said. He connected with educator Donald Salvatore at the Museum of Science in Boston.
Lewis credits Salvatore with “singlehandedly running” the Firefly Watch program from 2008 until his retirement in 2016.
“I think he did a really good job,” she said.
The first round of data collecting helped a group of European and U.S. scientists to use flash behavior (but not species identification) to study the overall abundance of fireflies in different geographical locations.
The Museum of Science, however, decided that without Salvatore, it didn’t want to continue the program. According to Lewis, the former educator shopped the program around and Mass Audubon agreed to take it on.
“They’ve really taken it over,” Lewis said.
Lewis has worked closely with the Mass Audubon team to ensure that the data will help scientists track and understand long-term population trends.
Firefly Watch is undergoing a few changes under Mass Audubon’s care, Lewis said. Its first incarnation was good, especially for gathering data on the number of flashes spotted by citizen scientists, she said. What it lacked, however, was the ability to identify species.
To help with species identification, the project team will roll out a series of “pro” in-person training and observation workshops. Firefly Watch is also working with the scientific crowd-sourcing website iNaturalist that can use picture and flash behavior submitted by users to identify species, said Lewis.
She calls iNaturalist “a powerful tool.”
According to Lewis, when people upload images to iNaturalist, the website uses two phases to identify the species of plant, animal, or insect. First it uses A.I. to ballpark the species and provide other information.
Next, living, breathing people review the image and information. A group of firefly scientists and citizens across the United States and Canada have made 9,000 observations over three years, said Lewis.
By having information on both flash behavior and species identification, scientists will be able to study how environmental conditions such as weather and climate are affecting specific species, she said.
An exercise in mindfulness
Initially, Jane Wheeler said her first year participating in Firefly Watch served as an experiment in mindfulness. She had recently completed a teacher-training program and was considering creating a series of workshops using nature to teach people to focus on the present moment.
She admits there was a bit of nostalgia for her childhood as well.
“Back when you’re a kid, it’s pretty magical” watching fireflies at night, she said.
That first year, Wheeler said she experienced a greater sense of awareness by paying attention and “getting to see something quite wonderful just in my backyard.”
She believes if more people stopped and practiced noticing — even the small things like fireflies — then they would build a stronger connection to their surroundings and the natural world.
Her desire to build more connection to the environment brought Wheeler back to the project a second year.
“This year, I would just miss it if I didn’t participate,” she said.
Firefly or lightning bug?
According to the Firefly Watch website, Lewis’s research has focused on the courtship and mating behavior of North American fireflies.
In a 2014 TED Talk, Lewis explains how fireflies use their chemical light to attract mates, about male fireflies’ “nuptial gifts,” and about female firefly vampires that trick males into becoming dinner.
People have misconceptions about fireflies, said Lewis.
First, people often think that “firefly” describes only one species. Try again: More than 2,000 species of fireflies live around the world.
People also forget — or never knew — that while the adults live for only a few weeks and rarely eat, they have “an amazingly long backstory” as juveniles, when they live in the ground and eat, eat, eat, eat and grow, grow, grow, grow.
Lewis explains in her writings and her TEDTalk that fireflies are one of several organisms that use chemical reactions in their bodies to create light. Many lifeforms in the oceans use this bioluminescence.
On land, some of the creatures that glow include fungi, earthworms, millipedes, and fungus gnats, writes Lewis.
The enzyme that sparks the production of light is luciferase, which works in tandem with a molecule, luciferin, which traps chemical energy between rings formed from a combination of carbon, nitrogen, and/or sulfur.
“Each luciferase consists of a large protein with a particular three-dimensional shape that allows it to coax its dance partner, always a much smaller molecule, into emitting light,” writes Lewis in an article at the TED website. “These smaller molecules are collectively known as luciferins, and they’re what actually produce the light that we see.”
According to Lewis, most people use “firefly” and “lightning bug” interchangeably. The lives behind these sparky insects, however, go much deeper.
Lewis said that fireflies belong to the beetle family Lampyridae. Approximately 200 species live in the United States, and approximately 2,000 species exist across every continent but Antarctica.
While all fireflies can trace their heritage to a common ancestor, they all have different habits.
“It’s more correct to say one family with three subgroups,” she said.
Not all fireflies light up as adults, Lewis explained. All, however, light as larvae.
“Lighting-bug fireflies” are a subset of the firefly family where the adults use “quick on-and-off flashes” to attract mates.
“Dark fireflies” are a subset where scientists believe the adults use chemical signals rather than bioluminescence.
The “glow-worm firefly” is a family where the female doesn’t fly or flash but glows for a long time to attract a mate.
Fireflies are most common in North America east of the Rocky Mountains. While patches of fireflies live west of the Rockies, they’re less prevalent because the environment tends to be too dry.
According to the Firefly Watch website, in North America, more than 150 species of fireflies in 16 genera inhabit North America. The three main groups of flashing fireflies are Photinus, Pyractomena, and Photuris.
“Just being beautiful and adding to the magical feeling we get in the summer is enough” to care about fireflies and their habitat, Lewis said.
There are other reasons to appreciate and protect fireflies, she continued. The firefly as both a juvenile and an adult “fits into the North American food web,” she said.
The juvenile larva eat slugs, snails, and soft-bodied grubs. These little beetles mean business: the young fireflies inject their prey with immobilizing toxins and digestive enzymes. The juveniles, in turn, are also eaten by other creatures.
The big threat: light pollution
The adult fireflies are all about finding mates, Lewis said, and different species have different sparkling courtship patterns.
Lewis said that one issue with light pollution, however, is that the female fireflies don’t flash as often when the environment is bright. This reduces their chance of finding mates, she said.
Not just the females are affected. Males of some species won’t flash, either, if too much light shines, she said.
Avalon C.S. Owens, a Ph.D. candidate working with Lewis, is studying how different wavelengths of light affect fireflies’ courtship patterns.
The hope is that Owens will identify firefly-friendly lighting that building owners can install to make the area around their buildings better for the beetles.
Owens holds a masters in entomology from National Taiwan University, where she studied the effects of artificial light on the flash behavior of urbanized Aquatica ficta, a species of firefly found in that part of the world.
In the meantime, Lewis recommends turning off all outdoor lighting during the local firefly season — yes, even those decorative, solar-powered garden lights.
For people worried about safety or stumbling around in the dark, Lewis recommends dimming the lights with a wattage as low as is comfortable or using motion-detection lights.
Remember the female fireflies are often on the ground looking up, Lewis said — a garden light that humans consider tiny is a “blinding sun” to a little firefly.
Lewis reminds people that if they want a lot of fireflies in their yards, they also need to provide habitat to attract them.
Adult fireflies and their nightly disco courtships get all the attention. But Lewis said that the beetles spend as many as two years as larvae, mostly underground eating as much as they can, including slugs, snails, and worms.
“They’re voracious predators,” she said.
The larvae basically eat until they’re ready to become adults. In colder climates, the cold-blooded larvae will also break for hibernation.
The juveniles hate to dry out, she said. They like moist ground with leaf debris and rotting wood in the vicinity.
Remember, fireflies don’t travel very far. They tend to be born and mate in the same area.
Dry springs and autumns aren’t great for the juvenile fireflies, Lewis added, and it is common to see fewer fireflies in the summer after a dry spring or fall.
On her blog (silentsparks.com/category/blog), Lewis cites the work of researchers who used data from Firefly Watch to see if they could predict how abundant the population would be in a season.
According to Lewis, the researchers found that the weather during a firefly’s youth “had a small but significant effect on the abundance of adult fireflies.” Along with soil moisture, the amount of precipitation juvenile fireflies experienced influenced how abundant — or not — the adult firefly population would be.
Also, remember that broad-spectrum pesticides hurt larva as it will any pests, she said.
Lewis said the first decision for those participating in Firefly Watch is to “pick a site” in their backyard, in their neighborhood, or anywhere they enjoy visiting. Then, they commit to the season for as long as possible.
The Firefly Watch website walks its citizen scientists through conducting observations and identifying flash patterns. Lewis’s book also includes field guides to identifying different kinds of fireflies as well as a wealth of information about the beetles from egg to adulthood.
Lewis advises people to keep an eye on the Firefly Watch website as well. The program is evolving and offering new information and in-person events.
For volunteers who have previously participated in the project, Mass Audubon is offering workshops called “Firefly Watch Pro.”
As one of the participants, Wheeler enjoys being a part of a larger project that is helping scientists all over the world.
“This may be a way of giving back and to pay attention again,” she said.
Wheeler laughs and says that observing fireflies brings its share of excitement — especially since she doesn’t carry a flashlight with her.
She remembers one quiet night she stood close to the forest’s edge of her backyard. She said she felt a little nose bump into her leg. She looked down and saw white stripes.
“I was so still and quiet that a skunk bumped into me,” she said.
She gasped. The skunk gasped. And she “booked it” back to her house.
“The look of surprise on that skunk’s face,” Wheeler recounted with a laugh.
Such moments illustrate Lewis’s hope to inspire people to put down the computer screens and step into the natural world.
“We’re surrounded by so many digital distractions, it’s difficult to find ways to stay connected to the natural world,” Lewis writes.
“But we won’t need to travel to remote wilderness to experience nature’s wonders — these silent sparks are right in our backyards and city parks, just waiting to be discovered.”