LAUSR

Abstract Insulin signaling is required for insect development. Insulin-like peptides and their signalings have been extensively assessed in various insects. However, little is known about them in Thysanoptera. This study identified the first insulin receptor in Thysanoptera using western flower thrips, Frankliniella occidentalis. A single Fo-InR (F. occidentalis insulin receptor) gene is encoded in its genome. A predicted amino acid sequence (1,645 residues) was highly (>70% homologies) matched to known insect InRs. However, it did not cluster with other known insect taxonomic groups. Domain analysis suggested an intracellular protein kinase and an extracellular ligand-binding regions. All developmental stages from larva to adult expressed Fo-InR. Starvation up-regulated its expression levels at all developmental stages except pupal stage. Different diet conditions resulting in different developmental rates altered expression levels of Fo-InR. There was a negative correlation between developmental rate and Fo-InR expression levels, especially at adult stage. Results of this study suggests a physiological role of insulin signaling in F. occidentalis development.