You Asked:

Can insects feel pain? — Darron, St. George, Grenada

Marshall Brain answered:

Let’s first take a look at how human beings feel pain. In our skin and throughout our muscles and joints we have pain receptors. These are nerve endings specialized for recognizing tissue damage. See How Aspirin Works for details on these receptors, known as nociceptors.

The nerves from these pain receptors run up the spinal column to the brain, where we feel the sensation of pain. There are also behaviors wired into the brain to help us respond appropriately to pain. Note that the spinal cord can respond to pain almost instantly – before the brain even gets the signal and starts to create the sensation.

An insect is completely different. First, there are no nociceptors found in insects. Second, because insects are invertebrates, they by definition lack a spine. Third, insects do not have centralized brains like people do. Instead, insects have clusters of nerve cells called ganglia distributed around the body. So insects do not have any way to feel “pain” like human beings do. That does not mean that insects lack sensation – they can sense when you grab hold of a leg, for example, and will struggle to get free. But this response is somewhat like the response we would see in a robot.

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