Molecular cloning and temporal–spatial expression of I element in gregarious and solitary locusts

It has been reported that many genes and small RNAs are associated with density-dependent polyphenism in locusts. However, the regulatory mechanism underlying gene transcription is still unknown. Here, by analysis of transcriptome database of the migratory locust, we identified abundant transcripts of transposable elements, which are mediators of genetic variation and gene transcriptional regulation, mainly including CR1, I, L2 and RTE-BovB. We cloned one I element, which represents the most abundant transcripts in all transposable elements, and investigated its developmental and tissue-specific expression in gregarious and solitary locusts. Although there are no significant differences of I element expression in whole bodies between gregarious and solitary locusts at various developmental stages, this I element exhibits high expression level and differential expression pattern between gregarious and solitary locusts in central and peripheral nervous tissues, such as brain, antenna and labial palps. These results suggest that I element is potentially involved in the response of neural systems to social environmental changes in locusts.