Two insulin receptors determine alternative wing morphs in planthoppers

Area of Science:

• Entomology
• Developmental Biology
• Evolutionary Biology

Background:

• Wing polyphenism, a trait in insects, involves alternative long-winged (flight-capable) and short-winged (flightless) forms.
• Environmental cues influence wing morph development, potentially mediated by hormones, but molecular mechanisms remain unclear.

Purpose of the Study:

• To elucidate the molecular mechanism controlling wing morph determination in the migratory brown planthopper, Nilaparvata lugens.
• To identify key molecular players regulating the developmental switch between long and short wings.

Main Methods:

• Investigated the roles of two insulin receptors (InR1 and InR2) in Nilaparvata lugens wing development.
• Analyzed the involvement of the phosphatidylinositol-3-OH kinase (PI(3)K)-protein kinase B (Akt) signaling pathway and the Foxo transcription factor.
• Examined the effect of the ligand Ilp3 on wing morph determination.

Main Results:

• InR1 and InR2 exhibit opposing roles in wing morph determination by regulating Foxo activity.
• InR1 activation promotes long wings, while its inactivation leads to short wings.
• InR2 negatively regulates the InR1-PI(3)K-Akt pathway; its suppression results in long wings.
• The ligand Ilp3 triggers the development of long-winged morphs.

Conclusions:

• Identified a molecular basis for wing polyphenism regulation in insects, involving opposing insulin receptor actions.
• Demonstrated a binary control mechanism for alternative developmental outcomes, enhancing understanding of phenotypic plasticity.
• Provided novel insights into the developmental pathways governing insect wing morph determination.