Species · GBIF taxon 6990480
Genji Firefly
Luciola cruciataAlso known as Genji-botaru, Genji Lightning Bug
Genji fireflies illuminate Japanese stream banks during early summer nights with a slow, synchronized rhythmic flashing. The aquatic larvae live in clean, running water where they hunt freshwater snails before pupating in the damp soil nearby. These beetles hold a deep cultural significance in Japan, celebrated in annual viewing festivals and serving as indicators of healthy, unpolluted freshwater ecosystems.
NocturnalBioluminescentAquatic Larvae
Licensed reference(c) Alpsdake, some rights reserved (CC BY-SA) · cc-by-sa
- diet
- Freshwater snails (larvae); nectar and dew (adults)
- family
- Lampyridae
- threats
- Water pollution, river channelization, and light pollution
- life Span
- 1 to 2 years
NE
Safe to observe at a normal distance.
Local populations have declined sharply due to river concrete-channeling, water pollution, and artificial light.
Never capture wild adults or disturb stream margins where larvae and pupae develop.- Avoid artificial light: Turn off flashlights and phone screens to prevent disrupting their mating flashes.
- Watch the weather: Look for them on warm, humid, windless nights after rain for the most active displays.
- Protect stream banks: Keep to designated paths to avoid crushing pupating larvae in the riverside soil.