The mimetic wing pattern of Papilio polytes butterflies is regulated by a doublesex-orchestrated gene network

<jats:title>Abstract</jats:title><jats:p>The swallowtail butterfly <jats:italic>Papilio polytes</jats:italic> is sexually dimorphic and exhibits female-limited Batesian mimicry. This species also has two female forms, a non-mimetic form with male-like wing patterns, and a mimetic form resembling an unpalatable model, <jats:italic>Pachliopta aristolochiae</jats:italic>. The mimicry locus <jats:italic>H</jats:italic> constitutes a dimorphic Mendelian ‘supergene’, including a transcription factor gene <jats:italic>doublesex</jats:italic> (<jats:italic>dsx</jats:italic>). However, how the mimetic-type <jats:italic>dsx</jats:italic> (<jats:italic>dsx-H</jats:italic>) orchestrates the downstream gene network and causes the mimetic traits remains unclear. Here we performed RNA-seq-based gene screening and found that <jats:italic>Wnt1</jats:italic> and <jats:italic>Wnt6</jats:italic> are up-regulated by <jats:italic>dsx-H</jats:italic> during the early pupal stage and are involved in the red/white pigmentation and patterning of mimetic female wings. In contrast, a homeobox gene <jats:italic>abdominal-A</jats:italic> is repressed by <jats:italic>dsx-H</jats:italic> and involved in the non-mimetic colouration pattern. These findings suggest that dual regulation by <jats:italic>dsx-H</jats:italic>, induction of mimetic gene networks and repression of non-mimetic gene networks, is essential for the switch from non-mimetic to mimetic pattern in mimetic female wings.</jats:p>