The serotonergic system is involved in feeding inhibition by pymetrozine. Comparative studies on a locust (Locusta migratoria) and an aphid (Myzus persicae).

Pymetrozine inhibits feeding in aphids immediately after application without producing visible neurotoxic effects, as previously reported. In the present work, Locusta migratoria, though not a plant-sucking insect, was found to respond to pymetrozine by displaying unique symptoms, which were lifting and stretching of the hindlegs, in addition to inhibition of feeding. In locust, pymetrozine enhanced spontaneous spike discharge of the metathoracic and suboesophageal ganglia in situ at nanomolar concentrations.