Abstract
The search for relatively safe pesticides to control pests continues to reduce the damage they cause and avoid the negative effects of pesticides on the environment. The red palm weevil (RPW), Rhynchophorus ferrugineus, is the most dangerous pest on palm trees of all kinds, especially in arid areas. Ivermectin (IVM), an analog of abamectin, shows physiological efficacy against insects at very low concentrations. This study was performed to evaluate the biochemical and histopathological effects of sublethal concentrations of IVM on cells of the testes and ovaries of R. ferrugineus. Mortality resulting from feeding IVM at concentrations of 2, 1, 0.5 0.25, 0.125 and 0.0625 ppm was estimated. The LC50 was calculated as 0.685 ppm for males and 1.23 ppm for females. Feeding the males and females at sublethal concentrations of 0.0625 ppm (LC15 for females, LC21 for males), 0.125 ppm (LC21 for females, LC28 for males) and 0.25 ppm (LC29 for females, LC37 for males) resulted in IVM concentration-dependent decreases in the activity of acetylcholinesterase and catalase and the content of glutathione accompanied by an increase in malondialdehyde. The histopathological effects of IVM concentrations of 0.25, 1 and 2 ppm indicate that IVM induced apoptosis in subcellular organelles of the testis and ovary. In conclusion, the results of this study revealed that sublethal IVM at 0.0625 ppm or higher induced reproductive toxicity in the RPW via redox disruptions and apoptotic cell death.