Capturing embryonic development from metamorphosis: how did the terminal patterning signalling pathway of Drosophilaevolve?

•The Torso activation module in insects is ancestrally involved in regulation of growth and pupation.•The Torso activation module has been co-opted into controlling terminal patterning in Drosophilaand Tribolium.•Torso-likeis highly conserved, but has a largely unknown function in embryogenesis and in the prothoracic gland.