Toxic effects of deltamethrin on oxidative stress, behavioural, organosomatic indices and histopathological changes in Digitonthophagus gazella (Coleoptera: Scarabaeinae).

Pyrethroids pose a great concern to the declining population of dung beetles and the sustainability of ecosystem services. This study aimed to investigate the toxic effects of deltamethrin on Digitonthophagus gazella. First, the LC₅₀ value (0.275 ppm) was determined, and sub-lethal concentrations (LD; low dose-0.014ppm, MD; medium dose-0.028ppm, and HD; high dose-0.055ppm) were assessed for physiological effects. The findings showed a significant dose and time dependent increase in fluorescence intensity (DCF-DA staining) and a decrease in antioxidant activity, including superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH). Furthermore, significant down regulation of cyp4g7, cyp6bq9, and cyp4q4 expression indicates enhanced oxidative stress. Additionally, a reduction in the organosomatic index, accompanied by histological changes in the brain, gut, and gonads, suggests potential functional disturbances. Overall, deltamethrin exposure had profound and irreversible pathological consequences on various vital organs and systems in D. gazella, affecting reproduction and nesting.