Research shows that insects feel pain, but not like human pain. The author of the research report said we don't really think insects feel pain. He said many insects can sense and avoid dangerous things they think will be painful. The author said: "We knew that insects could sense 'pain' but what we didn't know is that an injury could lead to long-lasting hyper-sensitivity...in a similar way to human patients' experiences."
The researchers looked at injured fruit flies. The scientists damaged one leg on fruit flies and let it heal. After the leg healed, the flies were more sensitive. They tried to protect their legs. The flies remembered the pain. This changed their behaviour. An injured insect becomes more sensitive until it dies. The researcher wants to do more research to understand how humans feel pain. He wants to make drugs to stop pain.