The development of artificial diets could considerably simplify and reduce the cost of mass rearing of natural enemies compared to conventional rearing methods. However, improvement of artificial diets can be tedious, convoluted and often uncertain. For accelerating diet development, a better method that can offer informative feedback to target deficiencies in diet improvement is required. Our previous research demonstrated several biological characteristics were diminished in the insect predator, Arma chinensis Fallou, fed on an artificial diet formulated with the aid of transcriptomic methods compared to the Chinese oak silk moth pupae. The present study reports differential proteomic analysis by iTRAQ-PRM, which unravels the molecular mechanism of A. chinensis responding to improvements in the artificial diet. Our study provides multivariate proteomic data and provides comprehensive sequence information in studying A. chinensis. Further, the physiological roles of the differentially expressed proteins and pathways enable us to explain several biological differences between natural prey-fed and improved diet-fed A. chinensis, and subsequent proposed reformulation optimizations to artificial diets.

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.

Greenhouse cage trials were conducted to evaluate the biocontrol potential of the predatory tiger fly Coenosia attenuata against the Chinese chive maggot Bradysia odoriphaga infesting Allium tuberosum. To ensure that adult C. attenuata have sufficient food when the B. odoriphaga adults decline or are absent, we supplemented the predator with alternative prey (Drosophila melanogaster adults), a banana-based banker medium, and a coir mulch layer across four treatments with three replicates per treatment over 50 weeks. When C. attenuata was released alone (T1), corrected control efficacy against B. odoriphaga larvae ranged from 56.14% to 59.82%. Notably, peak larval suppression was significantly higher in treatments combining the predator with a mulch layer (T2: 94.23%) or with the banker media system (T4: 100%). Against adult stages, T1 achieved 32.68–69.73% corrected efficacy, whereas T2 and T4 reached peak values of 100% and 97.69%, respectively. Predator application also doubled the total cumulative dry weight of Chinese chive. However, the concurrent use of banker medium and mulch layer (T3) did not produce synergistic effects. Collectively, these findings demonstrate that banker media systems and coir mulch layers are effective auxiliary tools for enhancing C. attenuata-based biocontrol in protected cultivation systems.