For centuries the common idea that animals feel pain just like us went unnoticed due to anthropocentrism. However, as time progresses, it seems that man has acquired the ability to generate empathy towards those beings that are nothing like him. And although little by little science has been discovering that animals also feel pain, one of the largest groups on the planet had been left out of research, until now that science has discovered that insects are also capable of feeling pain.
Previous research as well as anecdotal evidence showed that insects felt pain. But little by little science has found evidence that may point in the opposite direction. Recently three researchers from the universities of Queen Mary and Tehran found evidence that suggests that insects are capable of feeling pain.
Nociception and response to pain
It was already known that both animals and insects have physiological systems that are responsible for responding to painful experiences. But researchers have made a very clear distinction between responding to physical trauma and experiencing pain associated with the event.
For example, if an animal’s leg is cut, it is known that thanks to its physiological response system, it will show an immediate reaction to the fact of physical trauma. This response may result from evolutionary behavior, since it has been proven that insects also have reactions to avoid potentially harmful contact and thus bet on survival.
However, what was not clear is whether there is pain associated with such events. To clarify this doubt, the researchers used a method called ‘descending order of nociception’, where higher-level behavior can be associated with a harmful event.
It could be said that nociception is the detection by the sensory nervous system of unpleasant stimuli. These stimuli can include burns, sharp cuts and pressures that cause bruises, all of which generate an immediate physiological response that we know as the perception of pain, which is not the same as the response to a physical trauma event.
Insects feel pain
It has been shown that humans have independent regulators of nociception, that is, the perception of pain, and the reaction to the physical event. The human organism is so complex that in situations where an immediate response is warranted, such as continuing to run despite a major injury, the brain generates opiates capable of inhibiting nociception despite physical trauma.
This is why it was thought that insects do not perceive pain, since if so, they would also generate regulatory substances. But this new research shows that although insects do not generate opiates, they are capable of secreting a type of neuropeptides that could have the same function. These substances would be secreted by arthropods when they encounter traumatic events, which proves that they are capable of feeling pain.
The discovery sheds more light on the ethical debate about the treatment given to insects, the largest group of species that lives on the planet and that has been left out of the care of man when it comes to eliminating pests and research related to arthropods.
References: Sharlak, S. Gibbons, M. Chittka, L. Descending control of nociception in insects? The Royal Society. (2022), DOI