Insect populations have declined dramatically across many regions, with some studies reporting losses of over 75% in biomass over recent decades. These declines affect both ecosystem function and potentially involve enormous welfare consequences for individual insects.
Insect population decline presents a welfare dimension that intersects with genuine scientific uncertainty about insect sentience. If insects have no morally significant experience, their population decline is primarily a conservation and ecosystem services issue. If they have some form of experience — as the emerging evidence on nociception and learning in some insect species cautiously suggests — then population collapses represent welfare losses of staggering scale. The precautionary welfare approach takes seriously the possibility of insect experience without overstating the evidence, and recognises that the actions most likely to reverse insect decline — pesticide reduction, habitat restoration, and reduction of light pollution — are justified on conservation grounds even under uncertainty about welfare. The ecological and the welfare case for insect conservation are effectively aligned, making this an area where conservation and welfare advocates can work together.