Butterfly and moth populations are declining globally. Their welfare during habitat loss, pesticide exposure, and climate change, and in farming for educational and release events, raises emerging welfare considerations.
Butterfly and moth welfare sits at the frontier of welfare consideration where scientific uncertainty is high and precautionary approaches are reasonable. The evidence for caterpillar and adult lepidopteran sentience is weaker than for decapod crustaceans, but the scale of insecticide mortality and habitat destruction affecting billions of individuals warrants attention. Butterfly farming for mass release events raises welfare concerns about the conditions of captive rearing and whether mass releases negatively impact wild population gene pools. Monitoring and habitat protection are welfare-positive interventions regardless of the resolution of sentience questions.