The Roles of () in the Sex Determination and Fertility of , a Hemimetabolous Agricultural Pest.

In most holometabolous insects, () is an auxiliary gene required for sex determination, exerting a crucial role in regulating sexual differentiation; however, the study of in hemimetabolous insects remains very sparse and limited to just a few species. In this study, we investigated the sequence and expression profile of the gene in the bean bug, , an agricultural pest belonging to the Heteroptera order. Three non-sex-specific splicing isoforms of were found, , , and , which shared most exons and exhibited similar expression throughout all stages of development, with particularly elevated levels in the embryo, ovary, and testis. RNAi knockdown experiments revealed that the suppression of in nymphs led to abnormal females, characterized the formation of male-specific external genital, and also caused longer nymph duration. Knockdown of the expression of the gene in newly emergent virgin females would cause ovarian arrest, and injecting the 8th-day virgin females with ds also caused a noticeable decline in the offspring numbers. Conversely, in dstreated males, the testes maintained normal morphology but experienced impaired reproductive capacity, attributed to diminished sperm viability. These findings highlight the crucial role of in the sex determination and fertility of , providing valuable insights into the sex determination mechanisms of hemimetabolous insects.