Sex determination gene Doublesex in hemimetabolous insects

Sexual differentiation is a fundamental process in animals, which in insects is dependent on sex determination gene cascades rather than sex hormones. Notably, gene transcriptional regulation by the sex-determining gene Doublesex ( Dsx ), which encodes a transcription factor, plays a pivotal role in sexual differentiation among different insect species. Although its function is well conserved in holometabolous insects, it has undergone gradual evolutionary changes in hemimetabolous insects. In this review, we examine the male-specific role of Dsx in hemimetabolous insects by tracing its evolutionary trajectory based on recent findings. In particular, we focus on silverleaf whiteflies and termites, in which Dsx has undergone notable evolutionary modification, thereby highlighting their unique characteristics. • As a key transcription factor, Doublesex regulates sexual differentiation in insects • Hemimetabolous insects show gradual evolutionary changes in Dsx function • Recent findings reveal male-specific roles of Dsx in hemimetabolous insects • Silverleaf whiteflies and termites show unique Dsx evolutionary changes • The evolutionary trajectory of Dsx provides insights into insect sexual differentiation