Many insecticides primarily affect which part of an insect?

Insecticides are designed to disrupt specific physiological functions of insects, and many of them primarily target the nervous system. This is because the nervous system controls critical functions such as movement, feeding, and reproduction in insects. The mode of action for common insecticides, such as organophosphates and pyrethroids, involves interfering with neurotransmission—either by inhibiting enzymes that break down neurotransmitters or by blocking the transmission of nerve impulses.

When the nervous system is affected, it can lead to paralysis, disorientation, and ultimately death of the insect. This targeting of the nervous system is highly effective, as it directly impacts the insect’s ability to function and survive.

While other systems such as the respiratory system, digestive system, and exoskeleton are important for an insect's overall health and survival, insecticides are less commonly designed to primarily affect these areas. Respiratory toxins may lead to suffocation, and some insect growth regulators may impact the exoskeleton, but the predominant mode of action for most insecticides involves disruption of nervous system function.