Sexual dimorphism and wing polyphenism are important and evolutionarily conserved features of many insect species. In this article, we found a cross-talk linking sexual differentiation with wing polyphenism in the brown planthopper (BPH) (order: Hemiptera). Knockdown of the sex determination gene in () in nymph caused females to develop into infertile pseudomales containing undeveloped ovaries. Whereas males treated with ds exhibited normal morphology, but lost fertility. Knockdown of in adult females (maternal RNAi) resulted in long-winged female offspring, indicating that maternal RNAi changed the wing morphs in female offspring. In addition, silencing of down-regulated the expression of the transcription factor FoxO (), and simultaneously up-regulated the expression of (()) (), the two critical genes in the insulin signaling pathway. Furthermore, the long-winged effect caused by maternal ds RNAi could be reversed by silencing of and, leading to short-winged morphs. We propose that there is a cross-talk between the sexual differentiation and wing polyphenism pathways mediated by during embryonic stages.