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The question of whether insects feel pain appears to have new evidence in light of a recent study published in the journal Proceedings of the Royal Society in which researchers say insects should be included in animal welfare protections, particularly as population increases. insect breeding since insects feel pain, ‘probably’ because they have central nervous control of nociception (the detection of painful stimuli), just like humans.
Several lines of evidence suggest that the central nervous system of insects processes pain in a very similar way to ours. The justification , that insects do not experience pain as “higher” animals do, is questioned in this work.
Studies show that nociception and pain can be regulated independently of each other and have identified distinct systems for the regulation of each.
Animals (including insects) respond to these signals to limit damage to their bodies that could prevent their survival . The issue is whether insects experience pain through the central nervous system or whether the response is localized, for example to an injured limb.
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The study
The researchers reviewed the available scientific literature on the subject and found several lines of evidence suggesting that this mechanism is indeed present in insects. While they lack the opioid receptor genes that downregulate pain in us, they make other proteins during traumatic events that could serve the same purpose.
“Nociception is the detection of potentially harmful or actually harmful stimuli, which is mediated by specialized receptors: nociceptors,” said Professor Lars Chittka and colleagues from Queen Mary University of London. “It can be accompanied by the sensation of pain, which is a negative subjective experience generated by the brain. Nociception and/or pain can be inhibited or facilitated (modulated) by descending neurons in the brain (including the brainstem in vertebrates) called descending pain controls.
Based on behavioral, neuroscientific, and molecular evidence, the authors argue that insects likely have top-down controls for nociception.
“The behavioral work shows that insects can modulate noxious behavior,” the researchers said. “This modulation is controlled, at least in part, by the central nervous system, since the information that mediates said prioritization is processed by the brain.”
The world population is on track to reach 10 billion people by 2050 , and just the United Nations has recommended the mass production of insects for food. However, if the researchers are right and insects can feel pain, it raises ethical concerns about raising them for sustenance for humanity. Will we be able to continue treating them as we do if we discover that they are in pain?
“This is morally important , as insects are often subjected to potentially painful stimuli in research and agriculture,” the researchers write. “The possibility of pain sensations in insects is also an important consideration for modeling pain disorders in humans.”
Referencia: Matilda Gibbons et al. 2022. Descending control of nociception in insects? Proc. R. Soc. B 289 (1978): 20220599; doi: 10.1098/rspb.2022.0599
