Do insects feel pain when killed?

Whether insects feel pain when killed is a complex scientific and philosophical question that is still debated, with current research suggesting they likely experience nociception which is the detection of harmful stimuli but not pain in the human emotional sense. Insects including cockroaches, ants, and flies have nervous systems with sensory neurons that detect damage and cause avoidance behaviors, such as a cockroach moving away from heat or a bee learning to avoid a harmful stimulus, which is called nociception. However, pain as humans experience it involves not just detection but emotional suffering processed in brain regions like the cortex, which insects lack because they have a much simpler nervous system with a small number of neurons and no centralized brain comparable to vertebrates. Recent studies on fruit flies and bees show they exhibit some pain-like responses including prolonged sensitivity after injury and trade-offs between avoiding harm and seeking food, leading some scientists to argue they may have a basic form of pain experience. Other scientists argue these are reflexive responses without conscious suffering. From an ethical perspective, many pest control experts recommend humane methods where possible, such as quick-kill methods rather than slow-acting poisons that cause prolonged suffering, and using prevention and exclusion to avoid killing. For practical pest control, insects do react to being killed and will try to escape, but whether they subjectively feel pain as humans do remains unproven and is an active area of research in entomology and animal welfare science.