Glutaredoxin (Grx) is a group of redox enzymes that control reactive oxygen species (ROS), traditionally defined as redox regulators. Recent research suggested that members of the Grx family may be involved in more biological processes than previously thought. Therefore, we cloned the AcGrx5 gene and identified its role in A. chinensis diapause. Sequence analysis revealed the ORF of AcGrx5 was 432 bp, encoding 143 amino acids, which was consistent with the homologous sequence of Halyomorpha halys. RT-qPCR results showed that AcGrx5 expression was the highest in the head, and compared with non-diapause conditions, diapause conditions significantly increased the expression of AcGrx5 in the developmental stages. Further, we found that 15 °C low-temperature stress significantly induced AcGrx5 expression, and the expression of antioxidant enzyme genes AcTrx2 and AcTrx-like were significantly increased after AcGrx5 knockdown. Following AcGrx5 silencing, there was a considerable rise in the levels of VC content, CAT activity, and hydrogen peroxide content, indicating that A. chinensis was exposed to high levels of reactive oxygen species. These results suggested that the AcGrx5 gene may play a key role in antioxidant defense.

The circadian clock is a conserved timekeeping mechanism that enables organisms to anicipate and adapt to daily environmental cycles. While its role in photoperiodic diapause has been documented, its fundamental function in maintaining reproductive and metabolic homeostasis under favorable conditions remains less explored, especially in biological control agents. This study investigates the functional roles of the core circadian clock genes Cycle (AcCyc) and Clock (AcClk) in the predatory bug Arma chinensis, focusing on their regulation of reproduction and metabolism under non-diapause conditions. We characterized these genes and analyzed their spatiotemporal expression under diapause and non-diapause conditions. Using RNA interference, we knocked down AcCyc and AcClk in non-diapausing females and evaluated phenotypic impacts on ovarian development, fecundity, and energy reserves. qPCR analyses delineated downstream effects on juvenile hormone (JH) signaling. Results showed that diapause altered AcCyc and AcClk expression rhythms. Their knockdown severely impaired reproduction, reducing ovarian size, vitellogenin expression, and egg production, while concurrently decreasing triglyceride levels indicating disrupted energy homeostasis. Mechanistically, gene silencing downregulated key JH pathway components, Methoprene-tolerant (Met) and Krueppel homolog 1 (Kr-h1). We conclude that AcCyc and AcClk are essential maintainers of reproductive–metabolic homeostasis, not merely diapause regulators. This reframes the clock’s role from a seasonal timekeeper to a central hub for daily physiological coordination, offering new insights for improving biocontrol agent production.