Several UK bumblebee species have declined dramatically or become extinct in recent decades, with habitat loss, pesticides, and pathogen spillover from managed bees being key drivers.
Bumblebee individuals and colonies face welfare harms from pesticide exposure, pathogen infection, and nutritional stress from flower scarcity. Sublethal pesticide doses impair navigation, memory, and reproductive hormones. Parasitised colonies produce fewer queens and workers, with individual bees showing disrupted foraging behaviour. While insect sentience remains uncertain, the precautionary principle and the scale of decline both justify significant conservation action.