What characteristic do neonicotinoids primarily affect in insects?

Neonicotinoids primarily affect the nervous system in insects by acting as agonists at the nicotinic acetylcholine receptors. When insects are exposed to these chemicals, neonicotinoids bind to these receptors in a way that leads to continuous stimulation of the nervous system. This overstimulation results in the disruption of normal nerve signaling, which can ultimately lead to paralysis and death.

The specificity of neonicotinoids for the nervous system is what makes them particularly effective as insecticides. They target key pathways involved in neural communication without as heavily impacting mammals or birds, due to the differences in receptor structure and function between these groups. This characteristic is fundamental in understanding their mode of action and relevance in pest management strategies.