Fireflies have a potential -- protective 'musical armor' against bats

How do fireflies defend themselves against predators?

TEL-AVIV UNIVERSITY

Research News

 

IMAGE: NEW STUDY REVEALS: FIREFLIES PRODUCE STRONG ULTRASONIC SOUNDS THAT MIGHT DETER BATS, POTENTIALLY SERVING AS A KIND OF 'MUSICAL ARMOR' AGAINST THESE PREDATORS. view more 

CREDIT: BRANDON ALMS

A new study at Tel Aviv University reveals a possible defense mechanism developed by fireflies for protection against bats that might prey on them. According to the study, fireflies produce strong ultrasonic sounds - soundwaves that the human ear, and more importantly the fireflies themselves, cannot detect. The researchers hypothesize that these sounds are meant for the ears of bats, keeping them away from the poisonous fireflies, and thereby serving as a kind of 'musical armor'. The study was led by Prof. Yossi Yovel, Head of the Sagol School of Neuroscience, and a member of the School of Mechanical Engineering and the School of Zoology at the George S. Wise Faculty of Life Sciences. It was conducted in collaboration with the Vietnam Academy of Science and Technology (VAST). The paper was published in iScience.

Fireflies are known for their unique glow, used as a mating signal. Since their bodies contain poison, the light flashes probably also serve as an aposematic signal (a warning to potential predators). This signal is also the firefly's weakness, simply because it makes it an easy target for predators. Bats are among the fireflies' most prevalent potential predators, and some bats have poor vision, rendering the flashing signal ineffective. This led the researchers to check whether fireflies had some additional layer of protection against bats.

Prof. Yossi Yovel explains that the idea for this study came up accidentally, during a study that tracked bats' echolocation. "We were wandering around a tropical forest with microphones capable of recording bats' high frequencies, when suddenly, we detected unfamiliar sounds at similar frequencies, coming from fireflies," he recalls. "In-depth research using high-speed video revealed that the fireflies produce the sound by moving their wings, and that the fireflies themselves can't hear this frequency. Consequently we hypothesized that the sound is not intended for any internal communication within the species," adds Ksenia Krivoruchku, the PhD student who led the study.

Following the accidental discovery, the team at Prof. Yovel's laboratory examined three different species of fireflies that are common in Vietnam (Curtos Luciola, Sclerotia) plus one Israeli species (Lampyroidea), and found that they all produce these unique ultrasonic sounds, but cannot hear them.

Can it be concluded that fireflies have developed a special defense mechanism specifically for bats? Prof. Yovel emphasizes that this claim was not proved in the study, but several features do point to this conclusion. First of all, the fact that the fireflies themselves can't hear the sound, while bats can both hear it and use it to find the fireflies - so it's more likely that it serves as a warning signal. Krivoruochku adds that the discovery of ultrasonic sounds in fireflies is in itself an important contribution to the study of predator-prey relations: "The idea of warning signals that the sender itself cannot detect is known from the world of plants but is quite rare among animals. Our discovery of the 'musical battle' between fireflies and bats may pave the way for further research, and possibly the discovery of a new defense mechanism developed by animals against potential predators."

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UPDATED 

Biodiversity crisis: Habitat loss, pesticides and light pollution pushing fireflies to extinction, scientists warn
‘Warning bell’ for species as vulnerable ecosystems record impact of heavy industry

Harry Cockburn Tuesday, 4 February, 2020

Gleaming clouds of fireflies glow in a forest at dusk ( Getty )

Fireflies, of which there are more than 2,000 species strobing softly throughout dark corners of the world, are facing grave threats to their continued existence due to the impact of humans, a study suggests.

Habitat loss, pesticide use and artificial light are three of the most serious threats to fireflies, with certain species more at risk than others.

The widespread insects are soft-bodied beetles remarkable for their enchanting use of bioluminescence during twilight to attract mates or prey.

The health of firefly populations helps illustrate the impact humans have on sensitive ecosystems.

To better understand what threats are faced by fireflies, a team led by Professor Sara Lewis at Tufts University, Massachusetts, alongside the International Union for the Conservation of Nature, surveyed firefly experts around the world to assess the most prominent threats to survival for their local species.

Species to be protected by "blue belt" conservation zones

The research, published in the journal Bioscience, “sounds a warning bell” about the insects’ future, highlighting specific threats and the vulnerability of different species across geographical regions.

According to survey respondents, habitat loss is the most critical threat to firefly survival in the majority of geographic regions, followed by light pollution and pesticide use.

“Lots of wildlife species are declining because their habitat is shrinking,” said Professor Lewis.

“So it wasn’t a huge surprise that habitat loss was considered the biggest threat. Some fireflies get hit especially hard when their habitat disappears because they need special conditions to complete their life cycle. For instance, one Malaysian firefly (Pteroptyx tener), famous for its synchronised flash displays, is a mangrove specialist.”

Drastic declines have recently been recorded in this species after the destruction of their mangrove habitat to make way for palm oil plantations and aquaculture farms.

Across the world, light pollution was regarded as the second most serious threat to fireflies.

Artificial light at night has grown exponentially during the last century.

“In addition to disrupting natural biorhythms – including our own – light pollution really messes up firefly mating rituals,” said Avalon Owens, a co-author of the research paper.

Many fireflies rely on bioluminescence to find and attract their mates, and previous work has shown too much artificial light can interfere with these courtship exchanges. Switching to energy efficient, overly bright LEDs is not helping.

“Brighter isn’t necessarily better,” Ms Owens said.

The firefly experts also said the widespread use of pesticides in agriculture was another key threat to firefly survival.

Most insecticide exposure occurs during larval stages, because juvenile fireflies spend up to two years living below ground or under water.

Insecticides such as organophosphates and neonicotinoids are designed to kill pests, yet they also have off-target effects on beneficial insects. While more research is needed, the evidence suggests many commonly used insecticides are harmful to fireflies.

The paper acknowledges previous studies which have quantified firefly population declines, such as those seen in the tourist-attracting synchronous fireflies of Malaysia, and the glowworm Lampyris noctiluca in England.

Numerous anecdotal reports suggest that many other firefly species across a wide range of habitats have also suffered recent declines.

“We really need better long-term data about firefly population trends. This is a place where citizen science efforts like Massachusetts Audubon’s Firefly Watch project can really help,” said Professor Lewis.

The researchers also highlighted risk factors that allow them to predict which species will be most vulnerable when faced with threats like habitat loss or light pollution. For instance, females of the Appalachian blue ghost firefly (Phausis reticulata) are flightless.

“So when their habitat disappears, they can’t just pick up and move somewhere else,” said co-author J Michael Reed, professor of biology at Tufts.

Despite the verdict the researchers remain optimistic about fireflies’ future.

“Here in the US, we’re fortunate to have some robust species like the Big Dipper fireflies (Photinus pyralis),” said Professor Lewis.

“Those guys can survive pretty much anywhere, and they’re beautiful, too.”

By illuminating these threats and evaluating the conservation status of firefly species around the world, researchers aim to preserve the magical lights of fireflies for future generations to enjoy.

“Our goal is to make this knowledge available for land managers, policy makers, and firefly fans everywhere,” said co-author Sonny Wong of the Malaysian Nature Society.

“We want to keep fireflies lighting up our nights for a long, long time.”

Blinded by the light, firefly species face extinction

TUFTS UNIVERSITY/AFP / Jason STEELFireflies are beetles that glow to attract a mate

Fireflies are in deep trouble, with many species facing extinction due to habitat loss and exposure to pesticides, according to the first major review of their global status, published Monday.

Adding irony to injury, one of Nature's most entrancing spectacles is also being snuffed out by artificial light pollution, researchers reported in the journal BioScience.

More than 2,000 species of fireflies -- which are, in fact, beetles -- illuminate wetlands, marshes, grasslands, forests and urban parks worldwide.

A few, such as the Big Dipper in the United States, seem to be flourishing.

"Those guys can survive pretty much anywhere," said Sara Lewis, a biologist at Tufts University in Massachusetts and lead author of the study, based on a survey of dozens of firefly experts.

But other varieties -- from the glowworms of southern England to Malaysia's synchronous fireflies and the Appalachian blue ghost, both of which draw tourists -- are being extinguished by humanity's ever-expanding ecological footprint.

AFP/File / STRArtificial light, habitat loss and pesticides pose a grave threat to firefly species

"Some species get hit especially hard by habitat loss because they need specific conditions to complete their life cycle," said Lewis.

The Malaysian firefly Pteroptyx tener, for example, lives during its larval phase in riverside mangroves, many of which have been ripped up to make way for palm oil plantations and fish farms.

The glowworm (L. noctiluca) has another problem -- females are flightless, which means that can't simply buzz off to a new location when their habitat is swallowed by a suburb, commercial crop or country road.

Other species of fireflies, which eat only during their larval phase, are "dietary specialists," meaning they subsist on one or two kinds of snail, earthworm or other soft-bodied prey.

When fruit orchards in Mediterranean Spain are abandoned or give way to urbanisation, so too do the snails preferred by aptly named Lampyris iberica, leaving the firefly larva nothing to eat.

- 'Flashing through the gloom' -

Adult Pteroptyx in Malaysia, meanwhile, gather for nightly courtship displays in specific trees located along mangrove rivers. Many of those trees have been cut down.

Of 10 possible drivers of extinction, experts fingered habitat loss as the top threat everywhere -- except east Asia and South America.

In those two regions, artificial light was seen as the biggest menace to the world's luminescent beetles.

"In addition to disrupting natural biorhythms, light pollution really messes up firefly mating rituals," said co-author Avalon Owens, a doctoral student at Tufts.

Many species of firefly depend on their ability to light up to find and attract mates.

TUFTS UNIVERSITY/AFP/File / RADIM SCHREIBEROne of Nature's most entrancing spectacles -- fireflies -- is also being snuffed out by artificial light pollution

To make matters worse, that window of opportunity is very narrow: while the firefly larval phase lasts months to years, adults typically live only a few days.

The twinkling beetles are so focused on reproducing that they don't even eat.

The survey found that fireflies are also being decimated by commonly used insecticides, the third major threat.

"Organophosphates and neonicotinoids are designed to kill pests, yet they also have off-target effects on beneficial insects," the researchers wrote.

Fireflies light up by triggering a chemical reaction –- involving oxygen, calcium and an enzyme called luciferase -- inside special organs in their abdomen, a process called bioluminescence.

Their otherworldly glow has been an enduring source of fascination.

But firefly tourism -- long popular in Japan, Malaysia and Taiwan -- has also taken a toll, with fragile ecosystems damaged by too much foot traffic.

The plight of fireflies at the beginning of the 21st century add a new layer of meaning to lines written more than a century ago by Canadian poet Bliss Carman.

"And the fireflies across the dusk, Are flashing signals through the gloom," he wrote.

While climate change is not seen as a current threat, future sea level rise and drought also could accelerate the drive towards extinction.

The dozen authors contributing to the study are all affiliated with the Firefly Specialist Group -- set up in 2018 -- of the International Union for the Conservation of Nature (IUCN), which compiles the Red List of threatened species.

Fireflies face extinction risk - and tourists are partly to blame
By Georgina Rannard BBC News
 
GETTY IMAGES
Firefly tourism is growing in countries including Mexico, 
Japan, Malaysia and India

Firefly tourism is on the rise globally but scientists are warning it may contribute to risk of the insect's extinction.

"I spotted a hundred flickering lights, illuminating a palm like a Christmas tree."

"Our guide waved his flashlight at the fireflies. They slowly engulfed us - we were surrounded by a shiny galaxy of glowing beetle stomachs."

"I reached out a hand and captured one in my fist."

Reading this travel blogger's enchanting experience in 2019 makes it clear why firefly tours are popular, but done badly, it risks killing the insects.

Habitat loss and light pollution from urbanisation and industrialisation are the leading threats to firefly populations, according to research published this week.

But firefly tourism, which attracts thousands of visitors in countries including Mexico, the US, the Philippines and Thailand, is a growing concern for conservationists.

"Getting out into the night and enjoying fireflies in their natural habitat is an awe-inspiring experience," Prof Sara Lewis at Tufts University, who led the research, told the BBC.

But tourists often inadvertently kill fireflies by stepping on them, or disturb their habitat by shining lights and causing soil erosion.

Firefly festivals are organised in countries including Japan, Belgium, and India, and social media is magnifying this tourism, she adds.
How tourism can kill fireflies

The tiny town of Nanacamilpa in Mexico became a celebrated firefly spot in the past decade.

Some visitors post their sparkling photos on Instagram, flouting the ban on photography that many site managers impose, says local photographer Pedro Berruecos.

The Mexican fireflies are especially vulnerable to tourists, Prof Lewis explains.
Estimated annual visitors to firefly sites
Malaysia: 80,000
Great Smoky Mountains, Tennessee: 30,000 in two-three week summer season
Taiwan: 90,000
Mexico: 200,000 in 2019, up from 180,000 in 2018

The female insects are wingless and cannot fly, meaning they live on the ground, where visitors walking around will trample on them.

"No blame on the tourists, but if they walk on the forest floor, they will be standing on the female fireflies who will be carrying eggs. They are killing the next generation," Prof Lewis says.

In Thailand, Malaysia and the Philippines, the industry has existed for a few decades, but is usually poorly-managed, she explains.
PEDRO BERRUECOS
Firefly season is just three months in Mexico meaning the 
concentrated visits put extra pressure on the eco-system

Congregating Mangrove fireflies live exclusively in mangrove trees along rivers.

Males gather in huge numbers to attract females, producing the appealing glowing swarms that tourists desire.

Motorised boats are driven up the rivers, creating water swells that erode the banks, killing the trees where the fireflies live.

You might also like:
The 'unnoticed insect apocalypse': How people in towns and cities can help

"Operators also crash boats into the banks to disturb trees and make fireflies fly out, creating a swarm for tourists to see," Prof Lewis explains.

"There is evidence that even just camera flashes disturb fireflies and interfere with their reproductive success, in addition to the flashlights used by tourists".
Is firefly eco-tourism even possible?

Prof Lewis is keen to emphasise that firefly tourism is often crucial to local economies and should not be banned.

Instead tour operators and tourists can develop eco-friendly practices.
KATIE DIEDERICHSImage 
Travel bloggers rave about their firefly experiences - 
Katie Diederichs chose an eco-friendly tour operator

Travel blogger Katie Diederichs and her husband, both from the US, chose an eco-friendly tour operator in Bohol, Philippines for their firefly experience in 2015.

Travelling in a small group at night in kayaks with just one light, the experience was designed to be as unobtrusive as possible, Katie explains.

"The amount of light from the fireflies made the mangroves look like Christmas trees - it was really magical.

Chief Raoni Metuktire's fight to save the Amazon rainforest

"The male fireflies were flying around, giving the illusion of twinkling, while the females blink."

The company is run by locals who love the fireflies and want to protect their environment, she explains.

But Katie says they witnessed other operators with "large motorboat of tourists" passing by them "sending waves in our direction."
CARLA RHODES PHOTOGRAPHY

Wildlife conservation photographer Carla Rhodes snaps
 the Big Dipper Firefly in the Catskill Mountains in New York, US

In Taiwan, the tourist board has invested in sustainable firefly tours and created "thoughtful and effective" firefly eco-tourism, Prof Lewis explains.

Sites have regulated guided tours with raised walkways that allow small groups of people to walk through the habitat without trampling on fireflies.

Instead of flashlights or headlamps that would disturb the insects, white paint illuminates the routes.

A group of scientists will meet in 2020 to set down guidelines for how to run a sustainable firefly tourism company, Prof Lewis says.

A photographer's tips for snapping responsibly

"It is very important to not disturb the fireflies' habitat while photographing," advises wildlife conservation photographer Carla Rhodes.

She regularly photographs the Big Dipper firefly, as well as other wildlife, where she lives in the Catskill mountains in New York.

Watch where you walk, she says, and be careful with your light sources.

"And for goodness sake, please don't ever capture them!"



SEE  https://plawiuk.blogspot.com/search?q=FIREFLIES

 

Fading lights: Comprehensive study unveils multiple threats to North America’s firefly populations

As cities grow, they encroach on firefly natural habitats reducing their populations. A multi-university study is hoping to begin reversing the decline of this critical insect.

UNIVERSITY OF KENTUCKY

A landmark study conducted by the University of Kentucky Martin-Gatton College of Agriculture, Food and Environment; Bucknell University; Penn State University; and the USDA has shed light onto the precarious situation facing firefly populations across North America. The study’s results identified multiple factors impacting their numbers, offering a deep dive into how shifting environmental and human factors influence these iconic insects.

The study, published in Science of the Total Environment, “Illuminating Patterns of Firefly Abundance Using Citizen Science Data and Machine Learning Models,” identified the factors likely responsible for troubling declines in firefly populations across North America. To study these population changes, the research used a mix of field surveys from citizen scientists and advanced machine learning techniques to analyze over 24,000 surveys from the Firefly Watch citizen science initiative.

Key Findings

This research marks the first comprehensive attempt to apply a data-driven approach to understanding firefly population dynamics on a continental scale. Key findings from this new study indicate that fireflies, part of the beetle order, are sensitive to various environmental factors, from short-term weather conditions to longer climatic trends, including the number of growing-degree days related to temperature accumulations.

“Subtle changes in climate patterns, especially related to temperature, are significantly impacting firefly breeding cycles and habitat quality,” said Darin McNeil, study principal investigator and assistant professor of wildlife ecology and management.

Christina Grozinger, publius vergilius maro professor of entomology at Penn State University, said while scientists previously knew that urbanization, agricultural intensification and climate change can affect biodiversity, less was known about how these complex factors interact and what people can do in their own backyards, towns and cities to support biodiversity.

“In this study, we integrated large scale data sets on species abundance, land use, soil type, weather and climate using machine learning models to precisely model and predict firefly abundance patterns at the local scale across the eastern U.S.,” Grozinger said. “We were very fortunate to have a multi-year citizen science data set that spanned more than 24,000 observations.”

The study underscores fireflies' sensitivity to climatic variables such as temperature and precipitation. Fireflies thrive in temperate conditions, with wet and warm summers creating the ideal breeding environment and cold winters supporting the survival of immature stages like eggs, larvae and pupae.

However, as global temperatures rise, these conditions become less predictable and, often, less hospitable. Changes in precipitation patterns, another critical factor for firefly survival, have led to either overly dry conditions that reduce larval survival or excessively wet conditions that can flood breeding grounds and disrupt life cycles.

“Artificial lights at night could disrupt firefly populations, possibly affecting both adult and larval stages,” McNeil said. “Firefly larvae, which live in the soil, are particularly vulnerable to changes in light exposure and artificial light could alter their developmental cycles and survival rates. Firefly larvae, which are predatory, also require moist soil conditions because the humidity supports soft-bodied invertebrates like snails and slugs that firefly larvae use as prey.”

Urban growth, such as establishing impervious surfaces such as sidewalks, buildings and roads, poses a significant threat to firefly populations by invading natural habitats and decreasing available breeding areas. Light pollution from streetlights and commercial signs is particularly disruptive, as it interferes with the fireflies' bioluminescent communication essential for mating. The study indicates that fireflies are markedly less common in areas with significant nighttime light pollution.

Agriculture impact on fireflies

Certain agricultural practices also seem to contribute to the decline of fireflies. The extensive use of pesticides and herbicides has been linked to decreased firefly numbers, likely due to reduced prey availability and direct toxicity. This new study did not find a pesticide effect; in fact, certain agricultural areas supported some of the highest firefly densities, perhaps because some practices (e.g., livestock grazing) support meadow-like conditions that benefit fireflies. The study warns against increasing agricultural intensification, especially practices that reduce the organic debris and moist environments firefly larvae require to thrive.

The paper reveals that the decline in firefly populations is not uniform across all climates or regions. Some species adapted to dryer environments or those with specific breeding patterns may be less affected by certain changes, whereas others are more vulnerable. This highlights the complexity of natural ecosystems and the need for tailored conservation strategies.

The research team also made significant strides in identifying potential conservation measures to mitigate these impacts. These include reducing light pollution, preserving natural habitats and implementing wildlife-friendly agricultural practices that support fireflies.

Fireflies’ importance in the environment

The decline of fireflies is more than the loss of a beloved natural spectacle; it signals broader ecological disruptions that could have cascading effects on other species and ecosystems. Fireflies play a role in the food web, serving as prey for some species and as predators for many invertebrates. Their disappearance could have unforeseen repercussions on local biodiversity.

“As the study concludes, further research is encouraged, particularly in exploring the long-term trends of firefly populations and the efficacy of various conservation strategies” McNeil said. “Moving forward, focused studies that survey particular firefly species, rather than the firefly community as a whole, will be important. This approach will be crucial in ensuring that future generations can also enjoy the natural wonder of fireflies lighting up the night sky.”  

“Each individual species has its own habitat requirement and things it needs to succeed,” adds Bucknell University assistant professor of biology Sarah Lower, a noted firefly researcher. “With the citizen science data in this study, we’re looking at fireflies in the aggregate, but we would like people in citizen science getting more training in species identification. If we can get species-level information, we can provide more specifics on species living in a particular area and how best to protect them.”

To create similar data sets for other firefly species, the research team is also leveraging technology and AI to develop automated monitoring systems through an NSF funded INSECT NET graduate training program.

Individuals interested in learning more about the land use, weather and climate conditions in their locations can use Penn State's Beescape tool, which provides location-specific habitat quality scores for pollinators.

This work was funded by the Penn State Insect Biodiversity Center, Penn State’s Huck Institutes of the Life Sciences and Penn State’s College of Agricultural Sciences via the USDA’s National Institute of Food and Agriculture and Hatch Appropriations.

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JOURNAL

Science of The Total Environment

DOI

10.1016/j.scitotenv.2024.172329 

METHOD OF RESEARCH

Survey

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

Illuminating patterns of firefly abundance using citizen science data and machine learning models

COI STATEMENT

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Pitt mathematicians explain how some fireflies flash in sync

Peer-Reviewed Publication

UNIVERSITY OF PITTSBURGH

Stake out in Pennsylvania’s Cook State Forest at the right time of year and you can see one of nature’s great light shows: swarms of fireflies that synchronize their flashes like strings of Christmas lights in the dark.

A new study by Pitt mathematicians shows that math borrowed from neuroscience can describe how swarms of these unique insects coordinate their light show, capturing key details about how they behave in the wild.

“This firefly has a quick sequence of flashes, and then a big pause before the next burst,” said Jonathan Rubin, professor and chair of the Department of Mathematics in the Kenneth P. Dietrich School of Arts and Sciences. “We knew a good framework for modeling this that could capture a lot of the features, and we were curious how far we could push it.”

Male fireflies produce a glow from their abdomens to call out to potential mates, sending out blinking patterns in the dark to woo females of their own species. Synchronous fireflies of the species Photinus carolinus take it a step further, coordinating their blinking throughout entire swarms. It’s a rare trait — there are only a handful of such species in North America — and the striking lights they produce draw crowds to locations where the insects are known to gather.

They’ve also attracted the interest of mathematicians seeking to understand how they synchronize their blinks. It’s just one example of how synchronization can evolve from randomness, a process that has intrigued mathematicians for centuries. One famous example from the 1600s showed that pendulum clocks hung next to one another synchronize through vibrations that travel through the wall, and the same branch of math can be used to describe everything from the action of intestines to audience members clapping.

“Synchrony is important for a lot of things, good and bad,” said co-author Bard Ermentrout, distinguished professor of mathematics in the Dietrich School. “Physicists, mathematicians, we’re all interested in synchronization.”

To crack the fireflies’ light show, the Pitt team used a more complex model called an “elliptic burster” that’s used to describe the behavior of brain cells. The duo, along with then-undergrad Madeline McCrea (A&S ’22) published details of their model Oct. 26 in the Journal of the Royal Society Interface.  

The first step was to simulate the blinks of a single firefly, then expand to a pair to see how they matched their flashing rates to one another. Next, the team moved to a bigger swarm of simulated insects to see how number, distance and flying speed affect the resulting blinks.

Varying the distances each firefly could “see” each other and respond to one another changed the insects’ light show, they found: By tweaking the parameters, they could produce patterns of blinks that looked like either ripples or spirals.

The results line up with several recently published observations about real-life synchronous fireflies — for instance, that individual fireflies are inconsistent while groups flash more regularly, and that when new fireflies join the swarm, they’re already perfectly in time.

“It captured a lot of the finer details that they saw in the biology, which was cool,” said Ermentrout. “We didn't expect that.”

The math also makes some predictions that could inform firefly research — for instance, light pollution and the time of day both may alter the patterns produced by fireflies by changing how well they can see one another’s blinks.

McCrea worked on the research as an undergraduate supported by the department’s Painter Fellowship, which gave her funding to work on the project through the summer. “She was awesome working on this project, and really persistent,” said Rubin.

The team is the first to use this particular brain-cell framework to model fireflies, which several different research teams are trying to understand using different types of math. “It’s more of a wild west research topic,” said Ermentrout. “It’s early days, and who knows where things are going to go from here?”

Ermentrout and Rubin also hopeful that the math will capture the imagination of those inspired by the glow of fireflies. In the midst of this project, Rubin himself decided to head up to Cook State Forest to see if he could spot his research subjects firsthand.   

“I convinced my wife to go on a trip for a couple of days right in the peak of the season,” he said. “It’s not clear we ever saw synchronized activity, but there were all sorts of fireflies around us. It was amazing.”

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JOURNAL

Journal of The Royal Society Interface

DOI

10.1098/rsif.2022.0439 

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

A model for the collective synchronization of flashing in Photinus carolinus

 

Firefly tourism takes flight, sparking wonder and concern

First comprehensive review on the growing global phenomenon of firefly tourism

TUFTS UNIVERSITY

Research News

 

IMAGE: IN NORTH CAROLINA USA, MALE BLUE GHOST FIREFLIES (PHAUSIS RETICULATA) GLOW WHILE SEARCHING FOR MATES. THEIR FLIGHTLESS FEMALES ARE HIGHLY VULNERABLE TO TRAMPLING, AS THEY REMAIN HIDDEN ON THE FOREST... view more 

CREDIT: SPENCER BLACK

Firefly beetles rank among the world's most charismatic creatures, with luminous courtship displays that have now turned them into a popular attraction for wildlife tourists. In the first comprehensive review of firefly tourism, published in the journal Conservation Science and Practice, an international team of biologists led by a Tufts University researcher, reveal that an estimated 1 million people now travel each year to witness bioluminescent performances starring some two dozen firefly species around the world.

But the authors also point out that while this unique, insect-based tourism can bring economic, social, and psychological benefits to local communities and tourists alike, it also threatens to extinguish some local firefly populations unless adequate protections are put in place.

"With this review of the current state of firefly tourism and the declining health of their habitats, we are putting out a call to action to engage local communities and governments, as well as the tourists themselves, to act as guardians of the fireflies," said lead author Sara Lewis, professor of biology at Tufts University and co-chair of the International Union for the Conservation of Nature's (IUCN) Firefly Specialist Group, which conducted the review. The IUCN firefly group works to identify key threats and conservation issues facing fireflies in different geographic regions, and advocates for the most threatened species at national and global levels. Lewis' earlier work on fireflies with the IUCN has drawn considerable attention and fascination among the public and other researchers, with media coverage including CNN and The Washington Post.

In recent years, the number of tourists has skyrocketed at several sites in Mexico, India, Taiwan, Malaysia, Thailand, and the United States. "In Mexico, the rapid growth of firefly tourism over the past decade is thrilling but also alarming," said Tania López-Palafox, graduate student at Universidad Nacional Autónoma de México and co-author of the review. "The COVID pandemic gave them a momentary respite, but we have witnessed the harm that too much tourism can do."

Aimed at site managers, tour guides, and tourists, the report highlights the need to recognize ecological requirements across all firefly life stages. To promote the breeding success of firefly adults, sites should minimize light pollution: bright lights from buildings, vehicles, flashlights, and even cell phones - all of which can disrupt firefly courtship rituals.

CAPTION

Females of many firefly species lack functional wings, making them especially vulnerable to accidental trampling in areas of heavy foot traffic.

CREDIT

Radim Schreiber

Protection of nearby habitats also plays an essential role. Fireflies spend most of their life cycle in a juvenile, larval stage. These juveniles require several months or even years to develop into their adult form and, depending on the species, spend this time living below ground, in leaf litter or sometimes underwater. The authors describe former firefly sites along mangrove rivers where commercial development and excessive motorboat traffic have degraded riverbank habitat that had been essential for supporting firefly larvae.

At some sites, the reproductive cycle of firefly populations is threatened by tourists inadvertently trampling female fireflies and degrading larval habitats. Females in many species can't fly, and so are particularly susceptible to tourist foot traffic. Learn more about the mating rituals of fireflies studied by the Tufts research team in this video.

The report noted the popularity of displays created by several kinds of synchronous fireflies found in Southeast Asia and North America, where hundreds or thousands of firefly males captivate females - and tourists, too - by flashing their lights together in unison. According to co-author Anchana Thancharoen, lecturer at Kasetsart University in Bangkok, "With such mesmerizing lights, the firefly display trees make tourists fall in love at first sight. Our aim with this call to action is to channel that love into support for conservation efforts."

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Other recommendations by the authors include:

1) Tailored conservation practices to protect the habitats for all life stages to thrive
2) Involvement of local communities as ecological and economic stakeholders
3) Training programs for guides
4) Educational materials for visitors and best practices for transforming tourist behavior

Whether managed by local governments or run by commercial enterprises, well-managed tourism should educate global visitors to become allies in protecting firefly populations.

"There is also a larger opportunity here," said Lewis. "Fireflies hold a special fascination for people, and their fading lights make an obvious and visible case for conservation. But fireflies can also be a gateway bug to get tourists interested in conserving many other insects, which might not be so charismatic, yet still are essential building blocks for healthy ecosystems."

CAPTION

At Nanacamilpa in Mexico, tourists follow guides into the forest to view courtship displays of synchronous roving fireflies Photinus palaciosi

CREDIT

Tania López-Palafox

Enjoy the 'dazzling light show' of fireflies — but they also need protection, says researcher
CBC/Radio-Canada 2021-04-06

Females of many firefly species lack functional wings, making them especially vulnerable to accidental trampling in areas of heavy foot traffic.

Firefly tourism is brightening the spirits of people around the world, but without proper protections for the insect species, firefly populations could be at risk, according to new research involving a professor in Thunder Bay, Ont.

Harvey Lemelin, a professor with Lakehead University's School of Outdoor Recreation, Parks, and Tourism, is co-author of "Firefly Tourism: Advancing A Global Phenomenon Toward A Brighter Future," published in the journal Conservation Science and Practice.

Visits to firefly sanctuaries in Mexico, India, Taiwan, Malaysia, Thailand and the United States, for example, have skyrocketed in the past decade.

"We have a lot of internal tourism, or what we would call staycations during the pandemic," said Lemelin. "But we also have some people travelling across the world to go see these magnificent animals, especially North Americans, because apart from a few sites in Tennessee and the Carolinas, we don't get these large aggregations of fireflies.

"I do want to point out that the agencies and operators, sometimes, are withholding on their numbers," he said. "This international study, looking at 16 states across the world, calculated it to be a million visitors a year."

Fireflies, part of the beetles family, produce a chemical reaction that allows them to glow.

Lemelin said the interest in fireflies is easy to understand, especially when it comes to the groups of thousands of at a sanctuary.
Magical moments

"We ask the tourist to close their eyes, you wait about ... two minutes and then open your eyes," he said. "All the males are flashing at the same time, trying to out-compete each other

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© Sam Wolfe/Reuters Synchronous fireflies light up along the Bluff Trail at Congaree National Park in Hopkins, South Carolina. Firefly viewing is becoming very popular, with up to a million people visiting firefly sanctuaries around the world. However, experts warn that measures need to be put in place to protect firefly populations.

"It's like a magnificent, moving, dazzling light show, that no human being could ever replicate, and it's all around you," said Lemelin. "It is one of the most magical moments, and spiritual moments, I've ever had in my life."

But as beautiful as fireflies can be, Lemelin said proper steps must be taken to protect them, as the number of people viewing them increases.

"First of all, there's a carbon footprint of the travel," he said. "And then there's the on-site concerns.

"A lot of the managers and researchers were saying that, in the past, we've seen their habitats transform, so you're kind of losing the attraction," Lemelin said. "We've seen tourists increasing ... throughout the night, so the animals don't get a break from human beings."

Another problem is new lighting infrastructure, as fireflies are susceptible to light pollution, he said. Large crowds wandering off marked paths or away from designated viewing areas are an issue, too, as they may trample firefly larvae or non-flying females, and damage their habitats.
Protections needed

The article Lemelin co-authored includes some measures to prevent damage to firefly populations, including:
Implementing conservation practices to protect firefly habitat, and getting local communities involved.
Training programs for guides should be offered, as well, as should educational materials for visitors.

"Some of the places don't do a very good job of educating [tourists]," he said. "You've got a magical spiritual light show going on there. These individuals should be going home and asking, 'Why are there no fireflies aggregations in Canada? And what has happened to all their wetlands? What has happened to all of their habitats? How come we don't see fireflies the way we used to?"

Robotic lightning bugs take flight

Inspired by fireflies, researchers create insect-scale robots that can emit light when they fly, which enables motion tracking and communication

Peer-Reviewed Publication

MASSACHUSETTS INSTITUTE OF TECHNOLOGY

 

IMAGE: INSPIRED BY FIREFLIES, MIT RESEARCHERS HAVE CREATED SOFT ACTUATORS THAT CAN EMIT LIGHT IN DIFFERENT COLORS OR PATTERNS. view more 

CREDIT: IMAGE COURTESY OF KEVIN CHEN, SUHAN KIM,ET AL

Fireflies that light up dusky backyards on warm summer evenings use their luminescence for communication — to attract a mate, ward off predators, or lure prey.

 

These glimmering bugs also sparked the inspiration of scientists at MIT. Taking a cue from nature, they built electroluminescent soft artificial muscles for flying, insect-scale robots. The tiny artificial muscles that control the robots’ wings emit colored light during flight.

                 

This electroluminescence could enable the robots to communicate with each other. If sent on a search-and-rescue mission into a collapsed building, for instance, a robot that finds survivors could use lights to signal others and call for help.

 

The ability to emit light also brings these microscale robots, which weigh barely more than a paper clip, one step closer to flying on their own outside the lab. These robots are so lightweight that they can’t carry sensors, so researchers must track them using bulky infrared cameras that don’t work well outdoors. Now, they’ve shown that they can track the robots precisely using the light they emit and just three smartphone cameras.

 

“If you think of large-scale robots, they can communicate using a lot of different tools — Bluetooth, wireless, all those sorts of things. But for a tiny, power-constrained robot, we are forced to think about new modes of communication. This is a major step toward flying these robots in outdoor environments where we don’t have a well-tuned, state-of-the-art motion tracking system,” says Kevin Chen, who is the D. Reid Weedon, Jr. Assistant Professor in the Department of Electrical Engineering and Computer Science (EECS), the head of the Soft and Micro Robotics Laboratory in the Research Laboratory of Electronics (RLE), and the senior author of the paper.

 

He and his collaborators accomplished this by embedding miniscule electroluminescent particles into the artificial muscles. The process adds just 2.5 percent more weight without impacting the flight performance of the robot.

 

Joining Chen on the paper are EECS graduate students Suhan Kim, the lead author, and Yi-Hsuan Hsiao; Yu Fan Chen SM ’14, PhD ’17; and Jie Mao, an associate professor at Ningxia University. The research was published this month in IEEE Robotics and Automation Letters.

 

A light-up actuator

 

These researchers previously demonstrated a new fabrication technique to build soft actuators, or artificial muscles, that flap the wings of the robot. These durable actuators are made by alternating ultrathin layers of elastomer and carbon nanotube electrode in a stack and then rolling it into a squishy cylinder. When a voltage is applied to that cylinder, the electrodes squeeze the elastomer, and the mechanical strain flaps the wing.

 

To fabricate a glowing actuator, the team incorporated electroluminescent zinc sulphate particles into the elastomer but had to overcome several challenges along the way.

 

First, the researchers had to create an electrode that would not block light. They built it using highly transparent carbon nanotubes, which are only a few nanometers thick and enable light to pass through.

 

However, the zinc particles only light up in the presence of a very strong and high-frequency electric field. This electric field excites the electrons in the zinc particles, which then emit subatomic particles of light known as photons. The researchers use high voltage to create a strong electric field in the soft actuator, and then drive the robot at a high frequency, which enables the particles to light up brightly.

 

“Traditionally, electroluminescent materials are very energetically costly, but in a sense, we get that electroluminescence for free because we just use the electric field at the frequency we need for flying. We don’t need new actuation, new wires, or anything. It only takes about 3 percent more energy to shine out light,” Kevin Chen says.

 

As they prototyped the actuator, they found that adding zinc particles reduced its quality, causing it to break down more easily. To get around this, Kim mixed zinc particles into the top elastomer layer only. He made that layer a few micrometers thicker to accommodate for any reduction in output power.

 

While this made the actuator 2.5 percent heavier, it emitted light without impacting flight performance.

 

“We put a lot of care into maintaining the quality of the elastomer layers between the electrodes. Adding these particles was almost like adding dust to our elastomer layer. It took many different approaches and a lot of testing, but we came up with a way to ensure the quality of the actuator,” Kim says.

 

Adjusting the chemical combination of the zinc particles changes the light color. The researchers made green, orange, and blue particles for the actuators they built; each actuator shines one solid color.

 

They also tweaked the fabrication process so the actuators could emit multicolored and patterned light. The researchers placed a tiny mask over the top layer, added zinc particles, then cured the actuator. They repeated this process three times with different masks and colored particles to create a light pattern that spelled M-I-T.

 

Following the fireflies

 

Once they had finetuned the fabrication process, they tested the mechanical properties of the actuators and used a luminescence meter to measure the intensity of the light.

 

From there, they ran flight tests using a specially designed motion-tracking system. Each electroluminescent actuator served as an active marker that could be tracked using iPhone cameras. The cameras detect each light color, and a computer program they developed tracks the position and attitude of the robots to within 2 millimeters of state-of-the-art infrared motion capture systems.

 

“We are very proud of how good the tracking result is, compared to the state-of-the-art. We were using cheap hardware, compared to the tens of thousands of dollars these large motion-tracking systems cost, and the tracking results were very close,” Kevin Chen says.

 

In the future, they plan to enhance that motion tracking system so it can track robots in real-time. The team is working to incorporate control signals so the robots could turn their light on and off during flight and communicate more like real fireflies. They are also studying how electroluminescence could even improve some properties of these soft artificial muscles, Kevin Chen says.

 

 

This work was supported by the Research Laboratory of Electronics at MIT.

 

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Written by Adam Zewe, MIT News Office

Additional background

 

Paper: “Firefly: An Insect-scale Aerial Robot Powered by Electroluminescent Soft Artificial Muscles”

https://ieeexplore.ieee.org/document/9786652

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JOURNAL

IEEE Robotics and Automation Letters

DOI

10.1109/LRA.2022.3179486. 

ARTICLE TITLE

“Firefly: An Insect-scale Aerial Robot Powered by Electroluminescent Soft Artificial Muscles”