Despite invertebrates comprising the vast majority of animal species and being used in enormous numbers in research and industry, welfare research for this group remains severely underfunded.
Invertebrate welfare sits at the frontier of animal welfare science — a domain where the evidence for sentience is genuinely uncertain but improving rapidly, and where the scale of potential suffering is almost incomprehensibly large. The precautionary principle suggests that given uncertainty, welfare consideration should scale with probability of sentience and numbers affected. Insects alone are used in numbers that dwarf all vertebrate research combined. Bees, cephalopods, and crustaceans have attracted the most welfare research attention, but vast numbers of other invertebrate species receive no welfare consideration at all. Funding this research is one of the highest-impact areas in welfare science given the combination of scale, neglect, and tractability. Small improvements in how invertebrates are housed, handled, and killed could have enormous aggregate welfare effects.