Abstract
[Display omitted]
•The LC50 of imidacloprid (IMI) for Rhynchophorus ferrugineus females was 15.7 ppm.•Exposure to IMI inhibited ovarian AchE in a concentration dependent manner.•GSH was unchanged while CAT suddenly increased at IMI concentration of 30 ppm.•Lipid peroxidation increased as IMI concentration increased.•Acute IMI toxicity produced ultrastructure changes in follicle cells and ooplasm.
This study aims to inspect the effects of Imidacloprid (IMI) acute toxicity in the ovaries of the red palm weevil (Rhynchophorus ferrugineus). The LC50 of IMI was determined to be 15.7 ppm. We assessed the biochemical changes resulting from treatment with four IMI concentrations (10, 15, 20 and 30 ppm). IMI reduced acetylcholine esterase activity in a dose-dependent manner. Glutathione (GSH) content decreased with increasing concentration of IMI; however, GSH was not affected and accompanied by an increase in catalase activity with the highest concentration of IMI. Lipid peroxidation increased steadily as IMI concentration increased. Based on the ultrastructural analyses of the follicle cells and the ooplasm of developing oocytes, acute IMI toxicity produced damaged yolk bodies, pale nuclei, and shrinking microvilli. Fractionation of rough endoplasmic reticulum, deformed mitochondria, and autophagic bodies were also observed. In conclusion, these ovarian pathobiochemical changes could be used as biomarkers of acute IMI exposure.