Study Finds That Fireflies Are Now At Risk of Extinction
Tue, April 20, 2021

Study Finds That Fireflies Are Now At Risk of Extinction

Very few people know that fireflies are beetles belonging to the nocturnal members of the family Lampyridae. This is according to National Geographic, an American pay television network and flagship channel. Most fireflies are winged, making these animals stand out from other luminescent insects of the same family—glowworms. 

With about 2,000 firefly species, fireflies live in a variety of warm environments and in more temperate regions. Fireflies are also seen on summer evenings. These insects love moisture and are often found in humid regions of Asia and the Americas. In drier regions, however, fireflies are seen around wet or damp areas that retain moisture.

Fireflies are known for producing their signature glow. They have light organs under their abdomens. Fireflies take in oxygen, combining it with a substance called luciferin inside special cells to produce light. Those intermittent patterns of light are unique to each species and every blinking pattern is a signal for fireflies to find potential mates. The light may also be their defense mechanism to warn the predator that the firefly is an unappetizing meal. Fireflies are fascinating and beautiful insects, but they are now at risk of extinction.

Alarming Findings On Habitat Loss and Plummeting Insect Population

Francisco Sanchez-Bayo and Kris A.G. Wyckhuys of journal portal Science Direct published a study titled “Worldwide Decline of the Entomofauna: A Review of Its Drivers,” saying that over 40% of insect species are declining and may even lead to extinction, and a third of these species are endangered, cited Damian Carrington of British newspaper The Guardian. The total mass of insects has been declining by 2.5% each year over the last 25 to 30 years, suggesting that they could be extinct within 100 years.

Over the past decade, 41% of global insect species have fallen compared with 22% of vertebrate species. The researchers’ study identified agriculture— especially the heavy use of pesticides— as well as urbanization and climate change. Sanchez-Bayo said, “If insect species losses cannot be halted, this will have catastrophic consequences for both the planet’s ecosystems and for the survival of mankind.”

Sanchez-Bayo and Wyckhuys’s study gathered 73 of the best studies done to date to analyze the population decline of insects. For instance, butterfly species decreased harshly by 58% on farmed land in England between 2000 and 2009, according to a 2015 study by Andre S. Gilburn and colleagues of Peer J, an open access peer-reviewed scientific mega journal.

In Germany, a 27-year long population study published in 2017 revealed a 76% decline in flying insect biomass in 63 of the country’s protected areas, as found by Caspar A. Hallmann and colleagues of Plos One, a peer-reviewed journal portal. This was reported by Defend Democracy Press, the Delphi Initiative’s website. The findings represented a 2.8% average loss in insect biomass annually in habitats where there are rather low levels of human disturbance. 

Fireflies Are Now In Danger of Extinction

According to university press Oxford Academic, Sarah M. Lewis and her team conducted a study in 2020 titled “A Global Perspective On Firefly Extinction Threats,” where they noted that beetles have been successful insects since their evolutionary origin about 297 million years ago, representing 38% of known insect species. Fireflies are one of the most charismatic beetles, but they have also been largely neglected in global conservation efforts. 

The researchers sent a short Qualtrics survey via email to 350 people on the distribution list of the Fireflyers International Network. They grouped the respondents into eight regions: North America (US, Canada), Central America and Mexico, Europe, South Asia (India, Sri Lanka), East Asia (Taiwan, Hong Kong, China, Japan), and Southeast Asia (Thailand, Malaysia).  

The authors had only one respondent from Australia and South America and none from Africa. They only used the survey results from the respondents who provided scores for all threats, bringing the number to 49 firefly experts. Lewis and colleagues found that habitat loss, artificial light, and pesticide use were the three most serious threats when scores averaged across all eight regions.

Over half (55.1%) of the 49 experts assigned the highest threat score of 5 (0 being the lowest) to habitat loss. One-third (30.6%) of them did so for light pollution, while one-fifth (20.4%) gave a score of 5 for pesticide use. However, the respondents’ threat scores contrasted across geographic regions with threats such as water pollution and tourism ranked as important concerns in some areas.

Disrupting the Life Cycle of Fireflies

Fireflies suffer during times of habitat loss because they require certain environmental conditions to complete their life cycle, explained Lewis, who is also a professor of biology at Tufts University, as reported by Katie Hunt of American news channel CNN. Known for its synchronized flashing displays, one Malaysian firefly (Pteroptyx tener), for instance, needs mangroves and plants they contain to breed. But mangrove swamps all over Malaysia have been converted into aquaculture farms and palm oil plantations.

Artificial light includes direct lighting and skyglow. The latter refers to a more diffuse illumination that “spreads beyond urban centers and can be brighter than a full moon.” Co-author and PhD candidate in biology at Tufts Avalon Owens noted that light pollution messes up the mating rituals of fireflies. Since these animals rely on bioluminescence to find and attract mates, artificial light can interfere with the fireflies’ mating ritual. Using energy-efficient, overly bright LEDs are not helpful either, Owens added.

“Of course fireflies are particularly vulnerable to light pollution, more so than perhaps any other insect group, so it makes sense that this also emerges as a major concern,” said Dave Goulson, a professor of biology at the University of Sussex in the UK who was involved in the research. The study said over 23% of the global land surface currently experiences some degree of artificial brightness at night.

Firefly Tourism

Lewis and colleagues also considered “firefly tourism”— a recreational activity in Japan, Taiwan, and Malaysia where people watch spectacular light displays generated by fireflies— as a factor in the declining firefly numbers. Firefly tourism is becoming more widespread and popular, attracting over 200,000 visitors each year.

In Thailand, motorboat traffic along mangrove rivers destroyed trees and eroded riverbanks, resulting in habitat destruction. In North Carolina and Nanacampila in Mexico, tourists trampled flightless species of fireflies, as noted by the authors. Lewis and colleagues recommended establishing guidelines to manage tourist sites that highlight the best way to safeguard the fireflies from light pollution, trampling, and light pollution.

“Our goal is to make this knowledge available for land managers, policy makers, and firefly fans everywhere,” explained co-author Sonny Wong of the Malaysian Nature Society.  
Fireflies are spectacular insects, but we must be aware that they are now at risk of extinction. Some factors include habitat loss and light pollution. In places where firefly tourism is proliferating guidelines must be established to protect the animals and their habitat from being harmed and destroyed. This way, we can ensure that we will get to see fireflies light up the sky in the years to come.