Insects, Pain, And Robotics

Insects are widely used as model organisms for the study of animal behavior, genetics, molecular biology, and other issues. Yet the welfare of insects is only rarely discussed. This paper, published in Animal Behavior, touches on one important aspect of insect welfare. Specifically, examining whether or not insects are capable of feeling pain. The paper draws on evidence from four areas of research: philosophy, insect neurobiology and behavior, artificial intelligence and robotics, and evolution.

From a philosophical perspective, the authors note the readily observed capacity of insects to respond to potentially damaging stimuli, known as nociception. But they distinguish this from the capacity of insects to feel “a more subjective experience of discomfort, despair and other negative affective states.” Insects exhibit nociception that correlates with pain in humans, but some researchers believe the comparison may be invalid due to differences in nervous systems.

In this paper, the authors provide evidence from neurobiological research showing that the nervous systems of insects are simple when compared to mammals. The lack of a complex nervous system means that some researchers feel there isn’t compelling evidence that insects feel pain. The authors of this review ultimately determine that there is not enough “understanding of the neural architecture or minimum brain size required to support subjective experience” to reach a definitive conclusion.

Evidence from research on animal behavior is similarly equivocal. Experiments have shown that insects respond to noxious stimuli in ways that are both similar and different to humans, which is inconclusive. The authors also compare insect responses to that of robots, noting that robots can be programmed to demonstrate “pain-like behavior” even though they do not actually experience pain. From an evolutionary perspective, the authors say that insects would likely receive fewer benefits from having the ability to experience emotional pain compared to humans. They do concede, however, that “it is possible that experiencing pain emotionally is the conserved mechanism that evolution has hit upon to produce nociceptive-induced defensive states in insects and other animals.”

In conclusion, the authors agree with the prevailing notion in the scientific community that is it not currently possible to know if insects experience pain. They propose using one of two principle, including Morgan’s canon, a much-disputed doctrine holding that animal behavior should be attributed to the simplest possible processes. Alternatively, they suggest the precautionary principle: “it is better to err on the side of more protection for a group of animals if there is reason to believe that they experience pain.”

Most animal advocates would undoubtedly agree with the latter option. But the authors here take a middle ground and even warn that erring on the side of caution could lead to increased research costs and decreased capabilities. They also state, however, that “insects should be handled with care for reasons that do not hinge on whether or not they experience pain… all research animals should be handled in a way that reflects a respect for life, regardless of their ability to experience pain.”