小溪上方的萤火虫，冈山县，日本 Fireflies glowing above a stream, Okayama Prefecture, Japan (© tdub303/Getty Images)

小溪上方的萤火虫，冈山县，日本 Fireflies glowing above a stream, Okayama Prefecture, Japan (© tdub303/Getty Images)

流光之诗 The poetry of vanishing light

萤火虫发光在小溪上方，冈山县，日本

在冈山县（Okayama Prefecture），当湿润的空气笼罩在溪流之上，被称为“hotaru”的日本萤火虫便开始发出信号。在温暖无风的夜晚，如果条件理想，它们通常会在日落约两小时后开始发光，发散出一种水边独有的静谧感。

萤火虫并非蝇类，而是甲虫（Beetles），大多数种类栖息在水边，如池塘、溪流、沼泽和河流。白天，它们隐藏在低矮的草丛中；入夜后，它们爬上植被并起飞，通过闪烁光芒来寻找配偶。它们的光源自腹部的化学反应，而特定物种的闪烁频率有助于伴侣识别正确的信号。它们的幼虫生活在更安静且充满饥饿感的阶段：作为肉食性动物，幼虫以蜗牛和蛞蝓等软体动物为食；而成年萤火虫则可能采食昆虫、花蜜或花粉。

在日本，“萤狩”（Hotaru-gari，即观赏萤火虫）有着深厚的文化根基。平安时代（794–1185）的作家如清少纳言（Sei Shōnagon）曾在著作中描写过萤火虫，后世的文学作品和浮世绘（Ukiyo-e，一种传统的木版画和绘画形式）也常借其转瞬即逝的光芒来隐喻生命之无常。

Fireflies glowing above a stream, Okayama Prefecture, Japan

In Okayama Prefecture, when humid air settles over a stream, hotaru—Japan's fireflies—begin signaling. On warm, windless evenings, they often start glowing about two hours after sunset under favorable conditions, inviting silence beside water.

Fireflies aren't flies but beetles, and most species stay near water—ponds, streams, marshes, and rivers. By day they hide low in the grass; after dark they climb vegetation and take flight, flashing to find a mate. Their light comes from a chemical reaction in the abdomen, and species-specific timing helps partners recognize the right signal. Their young live a quieter, hungrier life: larvae are carnivores that feed on soft-bodied prey such as snails and slugs. Adults may eat insects, nectar, or pollen.

In Japan, watching them—hotaru-gari—has deep roots. Heian-era (794–1185) writers like Sei Shōnagon wrote about fireflies, and later literature and ukiyo-e art—a traditional form of woodblock prints and paintings—used their brief light to evoke impermanence.