title: Spinosad Induces Antioxidative Response and Ultrastructure Changes in Males of Red Palm Weevil Rhynchophorus ferrugineus (Coleoptera: Dryophthoridae).
abstract: The red palm weevil, Rhynchophorus ferrugineus, is of great concern worldwide, especially in the Middle East, where dates are a strategic crop. Despite their ecological hazard, insecticides remain the most effective means of control. A bioinsecticide of bacterial origin, spinosad is effective against several pests, and its efficacy against male R. ferrugineus was assessed in the present study. The antioxidative responses of key enzymes including catalase (CAT), superoxide dismutase (SOD), and glutathione-S-transferase (GST) to spinosad were investigated in the midgut and testes, and the effects of this insecticide on the cell ultrastructure of the midgut, Malpighian tubules, and testes were also determined. The lethal concentration 50 of spinosad was measured at 58.8 ppm, and the insecticide inhibited the activities of CAT, SOD, and GST in the midgut. However, no significant changes in the activities of these enzymes were observed in the testes. Spinosad treatment resulted in concentration-dependent changes in the cellular organelles of the midgut, Malpighian tubules, and testes of R. ferrugineus, and some of these effects were similar to those exerted by other xenobiotics. However, specific changes were observed as a result of spinosad treatment, including an increase in the number and size of concretions in Malpighian tubule cells and the occasional absence of the central pair of microtubules in the axonemes of sperm tails. This study introduces spinosad for potential use as an insecticide within an integrated control program against male red palm weevils. Additionally, the study provides biochemical and ultrastructural evidence for use in the development of bioindicators.
authors.affiliation: Department of Biological Sciences, Faculty of Science, King Faisal University, Hofouf, Saudi Arabia (sabdelraouf@kfu.edu.sa; aalzahra@kfu.edu.sa; oelmenshawy@kfu.edu.sa; aabdelmoneim@kfu.edu.sa) sabdelraouf@kfu.edu.sa.|Department of Zoology and Entomology, Faculty of Science, Assiut University, Egypt.
authors.forename: Salaheldin A
authors.initials: SA
authors.lastname: Abdelsalam
authors.affiliation: Department of Biological Sciences, Faculty of Science, King Faisal University, Hofouf, Saudi Arabia (sabdelraouf@kfu.edu.sa; aalzahra@kfu.edu.sa; oelmenshawy@kfu.edu.sa; aabdelmoneim@kfu.edu.sa).
authors.forename: Abdullah M
authors.initials: AM
authors.lastname: Alzahrani
authors.affiliation: Department of Biological Sciences, Faculty of Science, King Faisal University, Hofouf, Saudi Arabia (sabdelraouf@kfu.edu.sa; aalzahra@kfu.edu.sa; oelmenshawy@kfu.edu.sa; aabdelmoneim@kfu.edu.sa).|Department of Zoology, Faculty of Science, Al-Azhar University, Egypt.
authors.forename: Omar M
authors.initials: OM
authors.lastname: Elmenshawy
authors.affiliation: Department of Biological Sciences, Faculty of Science, King Faisal University, Hofouf, Saudi Arabia (sabdelraouf@kfu.edu.sa; aalzahra@kfu.edu.sa; oelmenshawy@kfu.edu.sa; aabdelmoneim@kfu.edu.sa).|Department of Zoology, Faculty of Science, Alexandria University, Egypt.
authors.forename: Ashraf M
authors.initials: AM
authors.lastname: Abdel-Moneim
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D002374:Catalase / Q000378:metabolism; D004338:Drug Combinations; D041981:Gastrointestinal Tract / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D005982:Glutathione Transferase / Q000378:metabolism; D019476:Insect Proteins / Q000378:metabolism*; D007306:Insecticides / Q000494:pharmacology*; D018942:Macrolides / Q000494:pharmacology*; D008297:Male; D008317:Malpighian Tubules / Q000187:drug effects / Q000648:ultrastructure; D013482:Superoxide Dismutase / Q000378:metabolism; D013737:Testis / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D048889:Weevils / Q000187:drug effects* / Q000201:enzymology / Q000648:ultrastructure*
chemical_list: D000975:Antioxidants; D004338:Drug Combinations; D019476:Insect Proteins; D007306:Insecticides; D018942:Macrolides; D002374:Catalase; D013482:Superoxide Dismutase; D005982:Glutathione Transferase; C415329:spinosad
keywords: Malpighian tubule; Rhynchophorus ferrugineus; Spinosad; antioxidant; midgut; testis; ultrastructure