Do Flies Feel Pain When You Spray Them?
WouterA common question posed by entomologists is “Do flies feel pain when you spray them?” Insects do not feel pain when sprayed. Instead, they feel irritation or damage to their bodies. Insects do not have emotions, so they do not experience pain directly, but receive pain messages through sensory neurons in their ventral nerve cords – insects’ spinal cord. They also have inhibitory neurons that act as gatekeepers, keeping pain signals in a single channel.
Pain is a subjective experience that consists of unpleasant feelings. In contrast, nociception – a response to harmful stimuli – is a universal mechanism shared by all organisms. Even bacteria and insects respond to stimuli – like pain – by moving away from dangerous environments.
Some fly sprays use chemical compounds to kill flies. These chemicals bind to an enzyme called acetylcholinesterase. This enzyme is responsible for regulating muscle contraction and therefore, fly sprays contain compounds that inhibit this enzyme. Consequently, the insect becomes nonviable, unable to move its abdomen and oxygenate its haemocele, and eventually dies as a result.
It is not clear whether flies feel pain after being sprayed by aerosols. Most flies don’t live very long, and most are killed by the sprays you spray on them. However, this doesn’t mean that sprays can’t kill ants and other insects. Although most insects are small and scurrying around, they will not be able to avoid the sprays.
