A monoamine neurotransmitter, 5-hydroxytrptamine (5-HT) or Serotonin is an important regulator of many behavioral and
physiological processes in both plants and animals. The involvement of 5-HT in the feeding behavior of different insect species
has been reported; however, the effect of this neurotransmitter on feeding behavior of Nilaparvata lugens is still not
investigated. Five distinct waveforms were observed by the feeding of N. lugens on sucrose diet using electropenetrography.
Present study proved that 5-HT significantly increased the time of first insertion of stylet into the diet at both 100 mg L-1
(26.97
min) and 1000 mg L-1
(89.90 min); however, no significant difference was observed in average and total time of ingestion by
N. lugens feeding on 5-HT. Ketanserin is the antagonist of 5-HT receptor which showed significant increase in average and
total duration of non-probing period at 25 and 100 mg L-1
. The mean percentage of ingestion significantly decreased while
insect feeding on 5-HT receptor antagonists mianserin hydrochloride and yohimbine hydrochloride. Methyldopa is the inhibitor
of aromatic L-amino acid decarboxylase enzyme which helps in synthesis of serotonin. It significantly increased the total nonprobing duration (218.45 min) but decreased (106.70 min) the total ingestion duration of N. lugens when feeding at 200 mg L1 concentration. 5-HT receptor antagonists reduced the feeding ability of N. lugens.
