Neonicotinoid insecticides have been shown to harm bee navigation, learning, reproduction, and immune function, representing one of the most significant documented welfare threats to pollinators.
Neonicotinoid welfare harms to bees operate primarily through sub-lethal exposure. Bees that survive exposure return to colonies with impaired navigation, disrupted communication, and reduced immune capacity. These effects at individual level translate to colony-level declines. Whether bees experience suffering from these impairments is uncertain, but the ecological and population consequences are clear. The precautionary principle applied at the scale of billions of bees justifies the strict regulatory response that many countries have implemented.