The phenomenon of synchronous fireflies is quite rare and absolutely spectacular. It occurs during some species of fireflies’ mating season. Lighting up is a way of communicating for these charming bugs. Their synchronised flashing tends to occur in certain places around the world around the end of May and throughout the middle of June. One of these places is Japan.Sometimes fireflies can light up an entire tree but most of them usually create a carpet of light in the woods. For lots of photographers, it’s quite a challenge to capture these little things. Partly because these bugs are nocturnal creatures and are afraid of light and even noise.In some cultures firefly may not have a positive reputation. But in Japan, where they are called "hotaru," they are beloved – a metaphor for passionate love in poetry since Man’you-shu (the 8th century anthology). Their eerie lights are also thought to be the altered form of the souls of soldiers who have died in war.
It is popular to view the fireflies’ glow during hot summer nights (hotaru-gari). However, since hotaru inhabit only clean streams, their numbers have been decreasing in recent years due to pollution.
"Hotaru no Hikari (The Light of the Firefly)" is probably one of the most popular Japanese songs.