How light pollution, habitat loss, and pesticide use are causing firefly population declines globally.
Firefly decline raises welfare questions that fall at the edge of moral consideration. Insect sentience remains scientifically uncertain, but fireflies represent sentient-candidate organisms experiencing population collapse from human-caused threats. Whether or not they have welfare in a philosophically demanding sense, their ecological role and cultural significance make their decline meaningful. Light pollution — a particularly tractable threat — can be addressed through individual and municipal lighting choices without significant cost. The same habitat and pesticide reduction strategies that benefit fireflies support the welfare of countless other species with clearer evidence of sentience.