Fireflies. Not a topic I think about often, if at all, but here we are. 

On a recent podcast episode, I learnt that the light that fireflies emit is nearly 100% efficient. That's amazing (nature generally is). And it is precisely the study of fireflies (and their light) that has allowed the development of more efficient LED lights. 

On a whim, I did a bit of extra Googling, and lo and behold, Japan pops up once more, with yet another culturally-unique eccentricity. 

In Japan, there are parks entirely dedicated to firefly-watching. Here a quote from the Wikipedia page: "Fireflies have attracted human attention since classical antiquity; their presence has been taken to signify a wide variety of conditions in different cultures and is especially appreciated aesthetically in Japan, where parks are set aside for this specific purpose."

Hotaru Matsuri (ホタル まつり) translates directly to 'firefly festival'; fireflies emerge from their larvae state to mate, and in most species the adults live for just a few weeks in the summer. As is the way of the natural world, breeding is the name of the game. The fireflies' bioluminescence is primarily for mate selection - it allows the fireflies to communicate with each other to find potential mates. Beginning around late-May, this also helps signify the changing of the seasons. 

In Japan, fireflies are bred and released in various parks in the summer period, and the result is a spectacular organic light show: 

Perhaps unsurprisingly, fireflies have a broader cultural significance in Japan, with their ethereal existence a metaphor for passionate love. Fireflies have been a notable part of Japan's literary canon, with poetry and literature that dates back to the 8th century. With the species declining, its nice to know that there are Firefly Courses to help with conservation efforts. 

More people may also be familiar with the film Hotaru no Haka, or Grave of the Fireflies, a Studio Ghibli-produced animated historical war drama film that's universally acclaimed. It's certainly one of the more depressing movies I've ever watched, but my god is it powerful and poetic. 

Pretty amazing, eh, for a bunch of light-emitting beetles.