In different parts of the world, locust swarms cause severe ecological and economic damage. However, the physiological mechanisms underlying this gregarization process remain elusive. In this study, we present a detailed quantitative analysis of two neuroparsin precursor (Scg-NPP1 and Scg-NPP2) transcripts in the brain, fat body, gut, gonads and accessory glands of male and female, gregarious and solitarious desert locusts (Schistocerca gregaria). These transcripts are generally more abundant in solitarious than in gregarious animals. In contrast to their gregarious congeners, solitarious locusts contain detectable Scg-NPP1 and Scg-NPP2 transcript levels in the fat body. Moreover, our data reveal temporal changes of neuroparsin mRNA levels in the brains and fat bodies of adult isolated-reared locusts. This paper provides the first scientific evidence for phase-dependent transcriptional regulation of neuropeptide hormone encoding genes.