Fireflies in Fukui,Lighting our way into summer
Measures of a healthy environment
September 19th, 2017
by Yoshihiro Hosokawa

The start of summer in Japan is traditionally announced by the appearance of fireflies.  Every year in June, these tiny, fantastic insects illuminate the darkness like dancing fairies.  They are plentiful in Fukui, particularly in Satoyama, an area of outstanding natural beauty, close to where Fukui locals live.  When you take a photo of glowing fireflies, you will be able to see rays of light bursting from them.   If you have a chance to see them at their peak, you will be amazed by the sight of countless little lights dancing around before your eyes.

Luciola cruciata, aquatic fireflies which live at the water’s edge, are the most famous kind of firefly in Japan.  They are between 1.5 and 2 cm long, and the males fly around, with their bright lights glowing, to attract females.  Their eggs are laid on moss, the larva live in fresh water, they change into cocoons in soil, and finally, they fly in the air.  In this way, the lifecycle of Luciola cruciata takes in all forms of the natural environment: water, soil, grass and air.   This balance needs to be prefect in order for them to thrive. This is the reason why Luciola cruciata are viewed in Japan as a measure of a healthy and clean environment.

Terrestrial fireflies, which are most often seen in the dense forests of Europe, might only be treated as curiosities there.  In Japan, however, aquatic fireflies are held in high regard, and are seen as something unique and wonderful, which enriches the Japanese landscape and natural environment.

Luciola cruciata can be seen flying around the water’s edge only for a short time each year; once flying, they live just for two weeks.  Japanese people feel great affection for the brief, transient life of the firefly; there is something deeply romantic and poignant about the delicate way in which fireflies shine their lights even until the last moments of their lives.

There is a strong sense of nostalgia attached to the firefly.  Before the 1960’s, there were much greater numbers of fireflies, that thrived in the unspoiled Japanese natural environment.  Children would wander down to the riverbanks, hand in hand with their grandfathers.  They enjoyed catching fireflies with nets or even brooms.  Fireflies were used to teach children about how imperfect, impermanent and incomplete life could be.

Fireflies began to decline following the rapid rise of Japanese industrial and economic growth, due to the destruction and pollution of natural habitats; waste drainage from the factories flowed into rivers, and farmers began to use agricultural chemicals to grow rice more efficiently.  Streams, where water for agricultural use was taken from, had their bottoms and sides covered not with soil but with concrete.  Thiaridal snails, which were the only source of food for the larva of fireflies, couldn’t live there anymore, and as a result, fireflies began to disappear.

As we entered the 2000s, many local campaigns were launched to reintroduce fireflies to areas all over Fukui.  For example, the local inhabitants of the Ago area raise the eggs of fireflies in a special environment and release the larva and imago into the Misarage River.  They have also continued to clean the river for many years until they saw the increasing number of fireflies.  Now, the Ago area is well-known for fireflies, and local maps are produced, showing visitors the best places to find fireflies.

The Fukui Firefly Association, which provides research and works towards the preservation of fireflies, helps educate children about the importance of conserving the natural environment.  Mr. Masao Yamashita, the chief guide of this group, tells people, “The areas you can see fireflies in are also the safest and healthiest environments for us to live.  Let’s preserve the ecological balance of these areas, with traditional methods.”

What children are watching is the imago and eggs of fireflies collected in the Misarage River.  These children from the city are fascinated by what they see with their own eyes.   They are overjoyed and can be heard exclaiming, “How nice!” and “This is like the illuminations.”  They are full of wonder at the sight of fireflies dancing around this 1 kilometer stretch of the river.

Fukui Prefecture has many rivers where you can enjoy nature: the Kuzuryu River, the Asuwa River, the Hino River, and the Kita River.  The Fukui Firefly Association publishes maps showing the best places to view fireflies, along these riverbanks.

Fireflies can live only for a short time, and they dislike strong lights; people who visit to view fireflies usually have to turn off their car headlights or flashlights.  Even if you happen to catch fireflies, it is good manners to release them back into the wild afterwards.  These scenes of fireflies flying and glowing is a treasured asset to the local areas, which have been inherited, restored and preserved with great care.





















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