Insects are extensively used in biological research, with growing evidence for pain-relevant nociception raising welfare questions about research practices.
Insect research welfare occupies the most uncertain territory of current welfare science. Drosophila research has revealed molecular nociception pathways - the biological machinery of pain detection - that are evolutionarily conserved from insects to vertebrates. Whether this machinery creates subjective pain experience in insects remains scientifically unresolved. The welfare implications depend entirely on this unresolved question - if insects experience pain, the billions used in research create substantial welfare considerations. The precautionary principle suggests at minimum refining insect research to minimize noxious stimuli and supporting research that resolves the sentience question.