Why are Fireflies Vanishing in the Philippines?
In local folklore, trees that are visited by fireflies or alitaptap are said to be the dwelling place of engkantos. People believed fireflies are servants or pets of these otherworldly beings. In Bicol, the elderly still pass this folklore to younger generations. But engkantos are dying, and so are the fireflies.
There are few places in the Philippines where fireflies were known to congregate in mass numbers: Ogod River in Bicol, Abatan River in Bohol, and Ihawig in Palawan. The insects would gather around the mangroves by the thousands and perform an ancient ritual of lights to locate their suitable mates.
Fireflies in Donsol, Sorsogon. Circa 2015
Several years ago, an aunt took a trip to Bohol. There, they were offered to go on a night boating trip on on the river to see the fireflies. For P3,000, they were promised a boat rental that would take them to the site of the fireflies. When they arrived, they were astonished.
“Iyan na ‘yon?” she exclaimed.
There were no fireflies.
She did not know that she had spent P3,000 on pure chance and no guarantee that the fireflies would show up. They settled for the glowing eyes of crocodiles—not an everyday sight, but not at all very reassuring either.
Around the Philippines, similar non-encounters are occurring. Yes, there are still fireflies, but fewer than in the past.
Where are the fireflies?
In the Philippines, fireflies have a wide range of distribution. They can even be seen in cities, if you are lucky. Their favorite habitat are the mangrove trees in the rivers. Fireflies lay their eggs in the muddy roots of the mangroves, where they hatch as larvae. The larvae feed on other insects and mollusks.
Fireflies are key indicators of an ecosystem’s health. Since they are very sensitive and react to the slightest changes in their environment, scientists use them in determining if something is wrong in a certain habitat. Often, it is people who are the cause of their vanishing.
Fireflies in Donsol, Sorsogon. Circa 2015
Pesticides from farms get washed away in the rivers where fireflies hatch their eggs, killing them in the process. Habitat loss is another factor. Although mangroves are protected under Philippine laws, some of the ecosystems that harbor them are not, like the Abatan River, which is still excluded from the list of protected areas under the National Integrated Protected Areas System of 1992.
Fireflies in Ogob River, Donsol, Sorsogon. Circa 2012.
Guess what? These are fireflies along the Ogod River in Donsol.— WWF-Philippines (@WWF_Philippines) May 20, 2016
The world is beautiful. Happy weekend, everyone! pic.twitter.com/t9RYgAw5Ym
Habitat loss is not just about cutting down mangroves, it is also about protecting the state of the ecosystems that nurture fireflies. One of the biggest threats to their survival is the use of motorboats along the river where they nest.
According to Culture Trip, motorboats wreak havoc on the Abatan’s ecosystem because their engines accelerate the erosion of mud underneath the mangrove trees where fireflies’ eggs and larvae develop.
Fireflies in Donsol, Sorsogon. Circa 2019
‘Firefly tourism’ is killing the fireflies
In a study about vanishing fireflies published in Bioscience in February 2020, lead author Sara Lewis discovered that apart from the destructive effects of pesticides, more damaging are the use of motorboats and artificial lights, which are killing the precious insects. Tourists often ride motorboats to get a glimpse of the spectacle of fireflies at night.
Firefly-Watching Guidelines at Donsol
According to the study, artificial light disrupts the biorhythms of the fireflies, messing up their mating rituals. Any light source brighter than a full moon is harmful to fireflies. That includes city lights.
“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,” biology professor Dave Goulson told CNN.
Fireflies are facing rapid extinction. But then again, who are these little insects to stop human expansion into their habitats? Maybe, just like the engkantos they serve, fireflies are meant to go extinct.