Benzoyl Carbamide Exposure and Ovipositor Dimensions in Sclerodermus sichuanensis: A Laboratory Study

Background: Chitin synthesis inhibitors are widely used in insect pest management; however, their potential sublethal effects on beneficial parasitoids remain an important concern for integrated pest management. Objective: This study investigated concentration-dependent variations in ovipositor length and width in adult female Sclerodermus sichuanensis following exposure to benzoyl carbamide. Methods: A total of 210 adult females were assigned to seven experimental groups, comprising an untreated control and six benzoyl carbamide exposure concentrations, with 30 individuals per group. Ovipositor length and width were measured following a 24-hour exposure period. Group-specific means and standard deviations were calculated from individual observations. Results: Both ovipositor dimensions exhibited progressive reductions across the exposure groups. Mean ovipositor length decreased from 1805.58 ± 58.57 µm in the control group to 465.60 ± 29.49 µm at the highest concentration, representing a 74.2% reduction. Similarly, mean ovipositor width declined from 865.98 ± 14.70 µm to 226.34 ± 21.15 µm, corresponding to a 73.9% reduction. At 30 mg/mL, ovipositor length and width decreased by 33.4% and 30.7%, respectively, relative to the control. Conclusion: Benzoyl carbamide exposure was associated with substantial, concentration-dependent alterations in ovipositor dimensions in S. sichuanensis. These findings highlight the importance of evaluating morphological responses in beneficial parasitoids when assessing insecticide compatibility with biological control programmes. Further investigations incorporating statistical testing, oviposition performance, and field-based assessments are warranted.