Astronomical Society of Wakabadai

Firefly and Light Pollution, adverse effects on ecosystem

1. Preface

Fireflies bring summer in Japan. Many of us still remember the dancing and flying illuminations full in the sky by nightfall. Well, how is this little creature remembered in other Asian countries?
In Philippines, these are creatures beloved by the people. Children would venture firefly-hunting, bring the catches back home and would be fascinated by mysterious illumination, though firefly becomes forgotten and neglected as children get older. They are still so common and can be found everywhere in Philippines. It is a story in Baguio, a summer resort.
Firefly is beloved and pretty also in Sri Lanka, although adults maybe too busy to notice them. Firefly is everywhere and many.
They are pretty and beloved creature in China too.

Please let us know how firefly is treated in your location. Send comments to

2. Firefly and Human-made Illumination

It is difficult to find firefly in Japan these days unless you would try to or visit special park where they are protected. Why are they disappeared? Water contamination, too much agricultural chemicals, concrete river banks; while these are making worse the living environment of firefly, human-made illumination is another reason that they cannot survive. According to Nobuyoshi Ohba of Nature Museum of Yokosuka City (Note 1.), human-made illumination would:

  1. Derange and disturb communications between fireflies,
  2. Restrain flight and illumination activities,
  3. Attract and derange male firefly,
  4. Disturb mating, and
  5. Particulary young firefly (larva?) stops illumination at minimal artificial light.

Mr. Ohba says "Life of Firefly cannot not be coexisted with human life."

Note: 1.
Kougai Tsushin (Light Pollution News, a magazine published by Hoshizora-wo-Mamoru-Kai)

3. Preserving Firefly Environment

Although it may be difficult for us to coexist with firefly at the same location, human can protect their environment and preserve their life. Researches on firefly teach us that the good controls of artificial light are needed near the life of firefly. These controls are also common in the activities of astronomers to save night sky and to promote quality outdoor lighting.
More places are becoming better places for them to survive, because the use of agricultural chemicals are restrained and water is clearer by controls on contaminants these days. We may expect their re-appearances in some locations. If the control of artificial light is realized and regulated, it will become possible to preserve this loving species at more and more locations.

4. Artificial Light and Its Problem

Artificial lights commonly and widely used in the public at this moment have the following problems. Most of these problems adversely affect the survival of fireflies.

  1. Glare: Direct light striking the eye, blinding the viewer, and the visibility is sacrificed; they also adversely affect the life of fireflies.
  2. Light Trespass: Spill light directed at where it is not welcome, brightening the verandah and rooms.
  3. Sky Glow: Human made light is illuminating the urban sky (upward direction) where no light is needed.

We know that the problems of artificial light, which is called "light pollution", adversely affect the life of firefly too. Glare, light trespass and sky glow; all of these problem affect their life. The mysterious illumination of firefly is restrained even at the time of full moon. It is a good evidence how much they suffer from human made illuminations.

At the same time these defective lighting system cause:

Waste of Electric Energy:
Lighting system which cause glare, light trespass and sky glow also waste electric energy.
Confusing night view:
Without proper lighting design, night view and environment is confused or even destroyed

5. Artificial Light and Other Adverse Impact on ecosystem

There are other reports of adverse effects on ecosystem by the artificial lighting.

  1. Impacts to agricultural products, rice plant, chrysanthemum, spinach
  2. Bad effects to the roadside trees
  3. Bad effects to Sea Turtle
  4. Another bad effects to Migratory bird

These are specific examples that poor lighting system is inadvertently giving documented impacts to the nature and only few people notice them.

6. Let us Plan Lighting System

It is clear that any lighting system should be planned and designed with such important factors in mind if we care energy savings, environment, and impacts on ecosystem. Most of lighting system in the public lacks such well organized planning from the beginning. They are just contracted with some vendors and installed without any consideration on the environmental affections.
"More-light-is-better-life" is hardly true. We have to realize that the lighting system without good planning does provide many bad effects even to the human beings who are living in the nature, not mentioning glare, light trespass, and sky glow. Human utility and life, environment (including preserving better night view and effects on ecosystem), energy savings and saving dark night sky; these are factors that the lighting design should be based on.
The Environment Agency and The Illuminating Engineering institute of Japan made a decision to write guidelines of lighting system to stop "Light Pollution" which causes sky glow and gives adverse effects on the astronomical observation due to the outdoor lighting.
Together and along with the official guidelines, more voices should be raised and quality lighting plan should be promoted in cities, communities and groups, not mentioning astronomers. If not we in local communities, who could materialize such solutions for lighting problems in nearby parks where firefly lives, at the roadside trees suffering from bad road light and so on.
Official guidelines takes time to be documented and more time will be needed to be actually enacted by the municipalities and on a specific lighting system itself.

7. Conclusions

Preserving firefly and promoting dark night sky have mutual benefits if we consider most factors and results as mentioned above. A point should be stressed that promoting quality lighting is not just one of activities of environmentalists but it is also one of major outstanding agenda of human beings who are living in the nature, in needs of precious energy, being adversely affected by air pollution and so on. We have realized the design of quality lighting system is the very subject we have to solve together for protecting our precious natural heritage.

When rainy season comes to end in June, and after a long and persistent rain, there comes surprise fire(-fly) works. They are unknown stars dancing and flying all over the sky. It looks just as if we are looking more stars everywhere even in your pocket. Farmers use rapeseed storks as bloom after harvesting its seeds. Let us bring the broom, go and get fireflies. It is a common picture in Asia that kids are chasing flies, singing, giggling and they are also dancing!

Preserving firefly and saving dark night sky; these are useful and promising activities for better human environment. Let us all join.

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This material is copyrighted by the Astronomical Society of Wakabadai. You are welcome to copy and distribute it for activities promoting quality lighting and saving dark sky.
The Society is established in January 1996 to offer children chances to see their own universe. Introduction to night sky is scheduled monthly by the use of slide and in star party. The society also promotes saving our natural heritage of dark night sky. The Society can be reached via e-mail at or by postal mail at 4-21-206 Wakabadai Asahiku, Yokohama, Japan 241.

Last update: 1996 August 11