A new study published in Science Advances reveals that fruit flies may feel chronic pain after an injury. While researchers have known that insects can feel pain (evidenced by their avoidance of stimuli that may be perceived as painful), they did not know whether insects developed chronic pain like people sometimes do after an injury.
The research team studied fruit flies with an amputated leg resulting in damage to the nerve. They exposed these flies to a heated surface. Normally flies are sensitive to heat and will escape from a surface that reaches 42 degrees Celsius, but the injured flies took off at even lower temperatures of 38 degrees Celsius. These observations suggest that the injured flies were more sensitive to temperature changes, which may indicate some form of chronic pain or hypersensitivity after their injury.
Researchers are hoping that understanding how chronic pain develops in flies may help pave the way for developing new treatments for humans with chronic pain as well.
Khuong TM, Wang Q-P, Manion J, Oyston LJ, Lau M-T, Towler H, Lin YQ, Neely GG. Nerve injury drives a heightened state of vigilance and neuropathic sensitization in Drosophila. Science Advances. 5(7), 2019. DOI: 10.1126/sciadv.aaw4099