There is something undeniably captivating and alluring about fireflies. In Silent Sparks: The Wondrous World of Fireflies, author Sara Lewis talks about the lives and surprising secrets of these creatures that light up the night skies. You’ll learn, for instance, that fireflies’ lives can be rather brief and gruesome. Lewis has spent over thirty years studying fireflies and has participated in a popular TED talk about the insects. This Q&A offers insights into why Lewis became so attracted to the idea of researching fireflies and what readers can expect to be surprised by in Silent Sparks.
What inspired you to write a book about fireflies?
SL: Ah, this book had quite a long gestation period! I’ve been doing research on fireflies for about 30 years. Whenever people hear about my job, “ Oh, I love fireflies!” is their nearly universal response. And so many people are curious, quite eager to learn more. But there really hasn’t been much accessible information out there. Even though we’ve learned a tremendous amount about fireflies over the past few decades, all these new discoveries lay hidden away in the technical literature. Scientists write primarily for other scientists, so these papers are chock full of technical jargon. Also, they can be difficult to access because they’re located behind paywalls. Knowing how many people would enjoy celebrating the science and the wonder of fireflies – that’s really what inspired me.
Who is the audience for this book, and what do you hope people will get from it?
SL: As I write in the preface: “If you love fireflies, then I wrote this book for you.” My goal is to escort people behind the scenes to explore the science behind the spectacle. How do these creatures make light? And what’s with all that flashing – are they talking to one another? What do baby fireflies look like? Are fireflies really disappearing?
One thing I hope people will take away from Silent Sparks is the immense beauty that emerges when you look at fireflies in the light of evolution. And they’ll get to glimpse the scientific process that helps us collectively accumulate knowledge. Of the few hundred scientists who’ve dedicated their days and nights to uncovering fireflies’ secrets, I’m lucky to count many of them among my mentors and friends. The book introduces quite a few of these firefly scientists – for me, their stories help the science come alive.
What’s most the surprising thing your book reveals about fireflies?
SL: Most people think there’s just one type of firefly, so the Most Surprising Revelation Award would likely go to the fact that there are over 2000 different firefly species sprinkled across the globe. And they’ve evolved remarkably different courtship styles. In North America, our most familiar fireflies are lightning bugs, which use quick, bright flashes to find mates. Northern Europe has mainly glow-worm fireflies: plump and wingless, these females climb up onto perches at night and glow for hours to attract their flying males. The western US has mainly dark fireflies. These fly during daytime and they don’t light up – instead males use their fancy antennae to sniff out perfumes given off by their females.
Any other surprises?
SL: Yes, lots! Without revealing too much, I think most people will be surprised by fireflies’ gory and gluttonous childhood, for instance.
Do you have a favorite firefly?
SL: I was hoping you wouldn’t ask that! It’s so hard to pick just one, because fireflies have so many different lifestyles and I find each one fascinating. I guess my current favorite would have to be the blue ghost firefly, Phausis reticulata. I fell under the spell of these mysterious fireflies a few years back when I first encountered them in the southern Appalachians. Flying ankle-high above the forest floor, blue ghost males give off eerie, long-lasting glows as they search for females. Meanwhile, the blue ghost females are tiny and wingless, and they’re very hard to find. They’re nestled down in the leaf litter, their transparent bodies studded with glowspots that shine like gemstones.
Another reason I like them is that they hold so many secrets just waiting to be uncovered – we still know very little these blue ghost fireflies.
What got you started studying fireflies?
SL: I got hooked on life’s diversity early on, but it wasn’t until I completed my PhD that I started paying close attention to fireflies. One evening I was sitting out in my backyard in North Carolina, and suddenly these silent sparks rose up all around me. It was a magical moment – anyone who’s seen them knows exactly what I mean! And when I started reading about them, I realized these creatures would make perfect subjects to better understand sexual selection. This evolutionary process is responsible for the many bizarre and unusual features that help males improve their reproductive prospects: the peacock’s tail, the rhinoceros beetle’s horns, the bowerbird’s displays, the wood thrushes’ song and, as it turns out, the firefly’s flashes.
What did you learn while writing this book?
In terms of my personal growth, I learned to love writing again. For this book project, I really wanted to make the science accessible. Yet scientific writing uses a highly precise, concise shorthand; jargon works really well when scientists are communicating with one another, but this language can be difficult for others to understand. It took a few months, but finally I remembered how much fun it is to write in plain English! Adjectives, punctuation…the possibilities were thrilling!
As I researched the book, I also learned a lot about the many interconnections between humans and fireflies. Around the world, fireflies elicit a nearly mystical reverence. But nowhere on Earth are fireflies more intricately woven into the cultural fabric than in Japan. As I describe in Silent Sparks, the Japanese people have enjoyed a profound love affair with fireflies for more than a thousand years. But I hadn’t realized how narrowly these beloved insects escaped being extinguished from the Japanese countryside during the twentieth century. Now, through research and widespread restoration efforts, Japanese fireflies have made a remarkable come-back to become a symbol of national pride and environmentalism.
Sara Lewis, who has been captivated by fireflies for nearly three decades, is a professor in the Department of Biology at Tufts University. Her work has been featured in numerous publications, including the New York Times, Scientific American, and USA Today. Lewis lives with her husband in Lincoln, Massachusetts.