Insect of the Week: Synchronous Symphonies

Among all the glamorous mating rituals that have been shaped by evolution, the displays performed by certain synchronously flashing fireflies might rank as the most spectacular. For reasons we don’t yet understand, only a few lightningbugs show a remarkable behavior: thousands of male fireflies will match up their rhythms to flash together in unison. Two distinct types of synchronous flash behavior have been observed: one type involves stationary males, while the other takes place among roving (flying) fireflies.

In southeast Asia, certain Pteroptyxmale fireflies sit in communal display trees along tidal rivers, where each night they spend hours flashing together in perfect synchrony. Females fly to these stationary aggregations, known as leks, where mating occurs.

Writing in the journal Science in 1935, Hugh Smith, a naturalist living in Thailand, described these dazzling displays:

Photo credit: Radim Schreiber

Imagine a tree thirty-five to forty feet high thickly covered with small ovate leaves, apparently with a firefly on every leaf and all the fireflies flashing in perfect unison at the rate of about three times in two seconds, the tree being in complete darkness between the flashes. Imagine a dozen such trees standing close together along the river’s edge with synchronously flashing fireflies on every leaf. Imagine a tenth of a mile of riverfront with an unbroken line of Sonneratia[mangrove] trees with fireflies on every leaf flashing in synchronism, the insects on the trees at the ends of the line acting in perfect unison with those between.

 

Because fireflies congregrate so predictably in the same trees, night after night for months, native boatmen once navigated among the twisting waterways using firefly display trees as landmarks.

But stationary flash synchrony doesn’t happen in any North American fireflies. Instead, several of our lightningbug species show a kind of wave synchrony, where flashes are synchronized locally among males flying within line-of-sight of each other. In the southern Appalachians, the synchronous symphony of Photinus carolinusattracts thousands of visitors to admire these flying males as they coordinate their six-pulsed courtship flashes with those of nearby males. These fireflies create waves of synchronous flashing that moves through the forest in the Allegheny National Forest and Great Smoky Mountains National Park. Similar displays of wave synchrony among roving males can be seen in mating displays of Photuris frontalis in Congaree National Park, South Carolina, Photinus knulli in Arizona, and Macrolampis palaciosi in Tlaxcala, Mexico. When they’re in a dense population, males of other fireflies will sometimes synchronize their flashes for a short time.

Wherever you find them, synchronous fireflies make an indelible impression – they are certainly one of Earth’s great natural treasures!

 

Learn more about firefly synchrony in Silent Sparks: The Wondrous World of Fireflies, and on the author’s firefly blog.

silent sparksSilent Sparks
The Wondrous World of Fireflies

For centuries, the beauty of fireflies has evoked wonder and delight. Yet for most of us, fireflies remain shrouded in mystery: How do fireflies make their light? What are they saying with their flashing? And what do fireflies look for in a mate? In Silent Sparks, noted biologist and firefly expert Sara Lewis dives into the fascinating world of fireflies and reveals the most up-to-date discoveries about these beloved insects. From the meadows of New England and the hills of the Great Smoky Mountains, to the rivers of Japan and mangrove forests of Malaysia, this beautifully illustrated and accessible book uncovers the remarkable, dramatic stories of birth, courtship, romance, sex, deceit, poison, and death among fireflies.

The nearly two thousand species of fireflies worldwide have evolved in different ways—and while most mate through the aerial language of blinking lights, not all do. Lewis introduces us to fireflies that don’t light up at all, relying on wind-borne perfumes to find mates, and we encounter glow-worm fireflies, whose plump, wingless females never fly. We go behind the scenes to meet inquisitive scientists who have dedicated their lives to understanding fireflies, and we learn about various modern threats including light pollution and habitat destruction. In the last section of the book, Lewis provides a field guide for North American fireflies, enabling us to identify them in our own backyards and neighborhoods. This concise, handy guide includes distinguishing features, habits, and range maps for the most commonly encountered fireflies, as well as a gear list.

A passionate exploration of one of the world’s most charismatic and admired insects, Silent Sparks will inspire us to reconnect with the natural world.

Insect of the Week: How to Make Your Yard More Firefly-Friendly

silent sparksYour neighborhood might have hundreds of fireflies, or maybe you have just a few. Perhaps you have none at all. No matter which, here are some simple things that will help make any yard more attractive to local fireflies.

Create an inviting habitat:
Fireflies need moisture during all of their life stages (that is, eggs, larvae, pupae and the adult).

  • Let the grass grow longer in parts of your lawn to help the soil hold more moisture.
  • Juvenile fireflies spend up to two years living underground, where they feed on earthworms and snails. If you leave some leaf litter and woody debris in the corners of your yard, this will help larval fireflies—and their prey—to thrive.
  • Female fireflies lay their eggs in moist, mossy places, so preserve any wetlands, streams, or ponds in your neighborhood.

Bring back the night:
Fireflies court using bioluminenscent flashes, so artificial lights that are too bright can interfere with their ability to find mates.

  • When installing or re-thinking your outdoor lighting, use only what you need to get the job done.
  • Use shielded lighting fixtures recommended by the International Dark-Sky Association; these direct light downward, where it’s most useful. Use bulbs as low-wattage as possible to provide just the light you need for safety and security.
  • Try turning off your outdoorlights, or put them on timers, particularly during firefly season.

Reduce pesticide use:
Because juveniles fireflies spend months living underground, they will come into contact with any insecticides spread on lawns and gardens. Broad-spectrum insecticides like malathion and diazinon will kill whatever insects they contact, including fireflies.

  • Consider using organic or least-toxic practices and products on your lawn and garden. Avoid broad-spectrum insecticides – use horticultural oils or insecticidal bacteria like Bt designed to target specific pests.
  • Apply pesticides to treat specific pest problems, never routinely.
  • Don’t use Weed & Feed or similar products that contain 2,4-D, which has been shown to be toxic to earthworms and beetles like ladybugs.

As I describe in Silent Sparks, our scientific understanding of firefly biology and habitat requirements has grown exponentially over the past few decades. Such knowledge now provides a powerful tool for protecting fireflies. And of course, we can all work to preserve and restore the wild places where fireflies thrive – their fields and forests, their mangoves and meadows. We all dream about the kind of world we want our children to inherit. Let’s make certain the magical sparkle of fireflies will continue to be part of their world.

Silent Sparks
The Wondrous World of Fireflies

For centuries, the beauty of fireflies has evoked wonder and delight. Yet for most of us, fireflies remain shrouded in mystery: How do fireflies make their light? What are they saying with their flashing? And what do fireflies look for in a mate? In Silent Sparks, noted biologist and firefly expert Sara Lewis dives into the fascinating world of fireflies and reveals the most up-to-date discoveries about these beloved insects. From the meadows of New England and the hills of the Great Smoky Mountains, to the rivers of Japan and mangrove forests of Malaysia, this beautifully illustrated and accessible book uncovers the remarkable, dramatic stories of birth, courtship, romance, sex, deceit, poison, and death among fireflies.

The nearly two thousand species of fireflies worldwide have evolved in different ways—and while most mate through the aerial language of blinking lights, not all do. Lewis introduces us to fireflies that don’t light up at all, relying on wind-borne perfumes to find mates, and we encounter glow-worm fireflies, whose plump, wingless females never fly. We go behind the scenes to meet inquisitive scientists who have dedicated their lives to understanding fireflies, and we learn about various modern threats including light pollution and habitat destruction. In the last section of the book, Lewis provides a field guide for North American fireflies, enabling us to identify them in our own backyards and neighborhoods. This concise, handy guide includes distinguishing features, habits, and range maps for the most commonly encountered fireflies, as well as a gear list.

A passionate exploration of one of the world’s most charismatic and admired insects, Silent Sparks will inspire us to reconnect with the natural world.

Insect of the Week: Five Myths About Fireflies

silent sparksMyth #1. Fireflies are flies, and lightningbugs are bugs

Truth: They have two different nicknames, but both refer to the same group of insects. Throughout much of the southern United States they’re called lightning bugs, while in the north and east they’re more often known as fireflies. Yet these insects are neither flies nor bugs – they’re actually beetles! What makes them beetles? Their hard wing covers that fold down to protect the delicate flight wings when the insect is resting.

Myth #2. If you’ve seen one firefly, you’ve seen them all

Truth: The firefly family, known as Lampyridae, includes more than 2000 described species worldwide. Here in North America, we have more than 200 different firefly species. These include the lightningbug fireflies, which use quick, bright flashes to find mates. These are mainly found east of the Mississippi River. But more common in the western U.S. are the glow-worm fireflies, which have glowing, wingless females, as well as dark fireflies, whose adults don’t light up at all.

Myth #3. Fireflies only light up for sex

Truth: In every species within the firefly family, the larval stage is capable of producing light. Because larvae are too young to reproduce, their bioluminescence appears to serve as an anti-predator warning. Fireflies contain chemicals that are toxic to many vertebrate predators. For these nocturnal larvae, bioluminescence is similar to the bright coloration used by monarch butterflies: it shouts out “I’m toxic – stay away!”

 Myth #4. Fireflies mean summertime

Truth: The spectacular summer lightshows produced by adult lightningbugs are just the tip of the firefly life cycle. Adult fireflies fly for merely a few weeks, but can spend nearly two years living underground during their larval stage. Juvenile fireflies spend months feasting on earthworms, snails, and other soft-bodied creatures. Ferocious carnivores, firefly larvae inject victims with paralyzing neurotoxins, then secrete digestive enzymes to liquify and ingest their prey.

Myth #5. There are so many fireflies, they don’t need protection

Truth: Certain firefly species, like the Big Dipper firefly Photinus pyralis, are abundant and occur in many habitats across a wide geographic range. But others are restricted to small, isolated populations or are habitat specialists, and these are in greater need of protection. Worldwide, many firefly populations are under threat from habitat loss, light pollution, and altered rainfall patterns due to climate disruption. In addition, firefly ecotourism is gaining popularity, and increasing numbers of visitors can impact both adult and larval habitats. Within the past century, fireflies in the U.S., Japan, and China have also been commercially harvested from wild populations.

 

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 Watertown, Massachusetts.


Silent Sparks
The Wondrous World of Fireflies

For centuries, the beauty of fireflies has evoked wonder and delight. Yet for most of us, fireflies remain shrouded in mystery: How do fireflies make their light? What are they saying with their flashing? And what do fireflies look for in a mate? In Silent Sparks, noted biologist and firefly expert Sara Lewis dives into the fascinating world of fireflies and reveals the most up-to-date discoveries about these beloved insects. From the meadows of New England and the hills of the Great Smoky Mountains, to the rivers of Japan and mangrove forests of Malaysia, this beautifully illustrated and accessible book uncovers the remarkable, dramatic stories of birth, courtship, romance, sex, deceit, poison, and death among fireflies.

The nearly two thousand species of fireflies worldwide have evolved in different ways—and while most mate through the aerial language of blinking lights, not all do. Lewis introduces us to fireflies that don’t light up at all, relying on wind-borne perfumes to find mates, and we encounter glow-worm fireflies, whose plump, wingless females never fly. We go behind the scenes to meet inquisitive scientists who have dedicated their lives to understanding fireflies, and we learn about various modern threats including light pollution and habitat destruction. In the last section of the book, Lewis provides a field guide for North American fireflies, enabling us to identify them in our own backyards and neighborhoods. This concise, handy guide includes distinguishing features, habits, and range maps for the most commonly encountered fireflies, as well as a gear list.

A passionate exploration of one of the world’s most charismatic and admired insects, Silent Sparks will inspire us to reconnect with the natural world.

 

Insect of the Week: the Darkest Fireflies

Bioluminescence lights up the larval stage in every member of this beetle family (Lampyridae), but adult fireflies have evolved remarkably diverse ways to find mates. Summertime icons that fill the night with their flashy courtship displays, the lightning bug fireflies might be the most spectacular. Yet many fireflies lose their bioluminescent spark once they become adults. These dark fireflies are active during the daytime, and females emit chemical signals to attract males. Phylogenetic evidence suggests that the common ancestor of all fireflies also had nonluminous adults. Though they are often overlooked, today these dark fireflies can be found coast-to-coast across the United States and Canada. Two groups of dark fireflies are particularly common. Once you learn to recognize them, you will see them everywhere!

A Lucidota atra firefly. Photo credit: Molly Jacobsen

Ellychnia includes a dozen or so different species with nonluminous adults. These dark fireflies are close cousins to the Photinus lightning bugs, but they have evolved a radically different lifestyle. Sometimes called Winter Fireflies, the adults spend the winter wedged down into grooves on tree trunks. They prefer trees with deeply furrowed bark, and dozens are often seen congregating on a single tree. After hunkering down for several months, surviving snow and freezing temperatures, Ellychnia adults are among the first insects to become active in the spring. Mating takes place in late March and April, when these hardy beetles can be seen flying slowly through wooded areas. Mating pairs, attached tail-to-tail, are commonly seen on tree trunks, where they remain coupled for 12 hours or more. It has been proposed that Ellychnia, which evolved from a nocturnal, Photinus-like ancestor, shifted to become day-active to escape night-time hunters like the predatory Photuris fireflies.

Lucidota atra is another day-flying, non-luminous firefly, and these adults are simply stunning. They are also easy to identify with their jet black wing covers, brightly colored head shield and flattened, saw-toothed antennae. These dark fireflies are commonly seen in early summer as they fly slowly, just a few feet above the ground, across lawns, fields, and forests. Experiments done by Jim Lloyd in the 1970s revealed that Lucidota females release pheromones that are carried on the wind, creating an invisible plume. Males seek out females by flying slowly back and forth until they encounter a plume, then fly upwind until they reach the female. The chemical nature of the female pheromone remains unknown.

 

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 Watertown, Massachusetts.

silent sparksSilent Sparks
The Wondrous World of Fireflies

For centuries, the beauty of fireflies has evoked wonder and delight. Yet for most of us, fireflies remain shrouded in mystery: How do fireflies make their light? What are they saying with their flashing? And what do fireflies look for in a mate? In Silent Sparks, noted biologist and firefly expert Sara Lewis dives into the fascinating world of fireflies and reveals the most up-to-date discoveries about these beloved insects. From the meadows of New England and the hills of the Great Smoky Mountains, to the rivers of Japan and mangrove forests of Malaysia, this beautifully illustrated and accessible book uncovers the remarkable, dramatic stories of birth, courtship, romance, sex, deceit, poison, and death among fireflies.

The nearly two thousand species of fireflies worldwide have evolved in different ways—and while most mate through the aerial language of blinking lights, not all do. Lewis introduces us to fireflies that don’t light up at all, relying on wind-borne perfumes to find mates, and we encounter glow-worm fireflies, whose plump, wingless females never fly. We go behind the scenes to meet inquisitive scientists who have dedicated their lives to understanding fireflies, and we learn about various modern threats including light pollution and habitat destruction. In the last section of the book, Lewis provides a field guide for North American fireflies, enabling us to identify them in our own backyards and neighborhoods. This concise, handy guide includes distinguishing features, habits, and range maps for the most commonly encountered fireflies, as well as a gear list.

A passionate exploration of one of the world’s most charismatic and admired insects, Silent Sparks will inspire us to reconnect with the natural world.

The bright world of fireflies: photographs from Silent Sparks

silent sparks jacketCharismatic, admired, and endlessly mysterious, fireflies have long been a source of intrigue. Sara Lewis has spent nearly thirty years examining the lives, surprising habits, and habitats of these beloved and frequently romanticized insects. As Memorial Day weekend winds down and fireflies start to make their debut in summer skies, take a peek inside the new book, Silent Sparks: The Wondrous World of Fireflies.

 

 

 

Q&A with Sara Lewis, author of Silent Sparks

silent sparks jacketThere 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.

silent sparks firefly

In blue ghost fireflies, the males can fly but the wingless females cannot. (photo by Raphael De Cock)

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!

silent sparks firefly

Fireflies spark childhood memories, transform ordinary landscapes, and rekindle our sense of wonder (photo by Tsuneaki Hiramatsu).

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.

8 Perfect Gift Books for Mother’s Day

Still stumped about gifts this Mother’s Day? Princeton University Press offers a great variety of choices for nature lovers, biography buffs, and more. Here are just a few unique ideas.

Cranshaw Jacket

Is your mother a garden lover? Garden Insects of North America: The Ultimate Guide to Backyard Bugs by Whitney Cranshaw is the ultimate book for common insects and mites that can be found in yards or gardens. Whether she’s interested in finding out what has been damaging plants, or simply wants a comprehensive identification guide, this book is a must-have.

bees

The Bees in Your Backyard: A Guide to North America’s Bees by Joseph Wilson and Olivia Messinger Carril offers tips for identification and debunks an array of myths about bees. With other 900 full-color photos, as well as tips on how to attract bees to your backyard, there’s no doubt this is a wonderful choice for someone who loves natural history, gardening, and insects.

silent sparks jacket

What could be more magical than fireflies?  Silent Sparks: The Wondrous World of Fireflies by Sara Lewis is a fitting choice for lovers of beauty, mystery, and the biology behind the scenes. Silent Sparks details why and how fireflies make their light, providing a tour of the different species that span the globe.

offshore sea life howell OffShore Sea ID Guide

No matter which coast your mother loves to visit, there are perfect guides available to help her identify sea life. Offshore Sea Life ID Guide: West Coast and Offshore Sea Life ID Guide: East Coast are both full of beautiful photos to assist in the identification of whales, dolphins, sea lions, sharks, and more. The guide is ideal for beginners and experts alike.

Living on Paper

For the mother who loves to settle down with a good biography, Living on Paper: Letters from Iris Murdoch is the perfect gift. The book is unique in that it is composed from over 760 of Murdoch’s personal letters, offering unprecedented insight into her life and personality.

Kroodsma

For mothers who love nature, memoirs, or birdsong, Listening to a Continent Sing: Birdsong by Bicycle from the Atlantic to the Pacific is a wonderful option. Author Donald Kroodsma intimately details his journey with his son across the country while they document birdsong.

the fourth pig mitchison jacket

Remind your mother of fairy tales read together, now with a twist. This collection of short stories and poems reimagines well-known tales like “The Little Mermaid” and “The Three Little Pigs”. This updated edition of The Fourth Pig by Naomi Mitchison is an intriguing bridge between childhood favorites and the darker versions adults save for themselves.

Happy Mother’s Day!