Watching a whole forestful of fireflies flashing together in unison is a truly mesmerizing experience. As I described in an earlier post, males of only a few firefly species are capable of this remarkable feat. Although we still don’t know why this behavior occurs, some researchers at the University of Colorado – Boulder recently developed cool tools to shed new light on how fireflies accomplish this collective behavior.
Using Go-Pro cameras to film Photinus carolinus in the Great Smoky Mountains National Park, Raphael Sarfati and Orit Peleg were later able to reconstruct the 3D flight paths of individual male fireflies. You can read about their study in this month’s Smithsonian Magazine, or check out their original paper in the Journal of the Royal Society Interface.
Their findings provide clues into how insects with relatively small brains can perform such seemingly complex synchronous behaviors. By demonstrating how fireflies kick off their synchrony, this research will inspire new advances in swarm robotics. In the future, their tracking methods could also be adapted for community science projects like Firefly Watch in the U.S. to help scientists monitor long-term trends in firefly populations.
Next we traveled to Malaysia, where I was once again fortunate to see some exciting firefly education and conservation projects in action. I’m excited to share a few with you!
Conserving urban green space: Bukit Kiara, a former rubber plantation turned urban park that lies smack dab in the middle of Kuala Lumpur. Along freshwater springs, biking, and walking paths the regenerating forest supports a healthy population of giant glow-worms (Lamprigera species). On our walk we found not only two gigantic wingless females (left-hand photo below), but also nearly a dozen glowing larvae moving rapidly across the forest floor as they searched for prey (middle photo). Females’ inability to fly severely limits the dispersal distance of these (and other) glow-worms, thus making them especially vulnerable to habitat fragmentation and loss due to encroaching urban development. By serving as a flagship species, these fireflies could help the advocacy group Friends of Bukit Kiara and other stakeholders convince the government to conserve this urban green oasis.
“The fireflies, twinkling among leaves, make the stars wonder.”
Rabindranath Tagore (1861-1941)
Well-managed firefly tourism: The Malaysian Nature Society empowers local communities by developing and sharing best practices for sustainable firefly tourism through their Firefly Kommunti, a network of firefly tour operators, nature guides and conservationists. This grass-roots initiative helps safeguard firefly populations while providing stable economic benefits for local communities. We visited Kuala Selangor Firefly Park in Kampung Kuantan, where standing oarsman take tourists along the mangrove river in traditional wooden sampans to see display trees sparkling with synchronous Pteroptyx tener fireflies. To restore firefly habitat in areas where riverside vegetation has been cleared, river protectors in the Inspirasi Kawa youth group have replanted saplings of berembang trees (Sonneratia caseolaris), favored by these synchronous fireflies for their spectacular courtship displays.
All the collaborative projects I witnessed – bringing together local NGOs, community members, industry, and conservationists – gave me real hope that we can work together to keep firefly magic alive!
Synchronous fireflies certainly highlight Earth’s natural magic, yet such cooperative behavior presents quite a thorny scientific paradox!
We do know how some fireflies manage to synchronize their flashing, thanks to work done in the 1960’s by John & Elisabeth Buck (previous post). For instance, male Pteroptyx fireflies in southeast Asia can reset their internal timekeeper whenever they see a neighbor’s flash. Inspired by Steve Strogatz’s book, Sync, Nick Case made a spectacular simulation to illustrate how this works – I’ve played with it for hours, and you can, too!
Synchronous fireflies in the Great Smoky Mountains
But why do fireflies synchronize? Why should thousands of males so carefully coordinate their behavior to flash in unison, all of them marching to the beat of a single drummer? According to sexual selection theory, these males should be competing fiercely with each other for the chance to mate. So why synchronize?
About 15 years ago we held a family reunion near a small lake in the Blue Ridge Mountains, near Saluda, NC. It was around July 4th, so around the lake lots of people were setting off fireworks. We were gathered by the lake near a wide grassy area that led right up to the base of the mountain. That night the fireflies appeared around dusk, just when the fireworks started. Although the fireworks were going off much higher up, we realized that down below the fireflies’ flashing was gradually getting synched up with the fireworks. As it got darker, the coordination seemed to increase so that every time a firework went off, the fireflies would light up, all pretty much at the same time.
It was a magical scene – a constellation of yellow-green flashes lighting up down near the ground, triggered by the dramatic firework explosions in the sky. And the fireflies earned much bigger “ooooohs!” than the fireworks! Only later did I learn that what we were seeing were probably the romantic signals of male Photinus carolinus fireflies, flashing together like one big mega-male to try to win the favor of their females.
Stop what you’re doing and watch this short video taken in Samut Prakan province, Thailand. Turn off the lights, go full screen, and get ready to be blown away by thousands of male fireflies regularly synchronizing their flashes to attract females. They synchronize naturally, although here the fireflies (known as Pteropytx malaccae) have been triggered by some flashing LED lights. This video is part of a 2015 installation work by Robin Meier & Andre Gwerder, it’s called “Synchronicity (Thailand).”
You can also watch some spectacular displays of the U.S. synchronous firefly, Photinus carolinus, which lives parts of North Carolina, Tennessee, and Pennsylvania. You can read more about these traveling synchronizers in Silent Sparks (Chapter 2: Lifestyles of the Stars).
Produced by Audemars Piguet Art Commission, Le Brassus
Director of Photography: Nikolai Zheludovich; Editing: Mariko Montpetit
Special thanks to Anchana Thancharoen and her team at Kasetsart University, Bangkok