title: Selectivity of diacylhydrazine insecticides to the predatory bug Orius laevigatus: in vivo and modelling/docking experiments.
abstract: BACKGROUND
  Knowledge of pesticide selectivity to natural enemies is necessary for a successful implementation of biological and chemical control methods in integrated pest management (IPM) programmes. Diacylhydrazine (DAH)-based ecdysone agonists, also known as moulting-accelerating compounds (MACs), are considered to be a selective group of insecticides, and their compatibility with predatory Heteroptera, which are used as biological control agents, is known. However, their molecular mode of action has not been explored in beneficial insects such as Orius laevigatus (Fieber) (Hemiptera: Anthocoridae).
  
  
  RESULTS
  In this project, in vivo toxicity assays demonstrated that the DAH-based RH-5849, tebufenozide and methoxyfenozide have no toxic effect against O. laevigatus. The ligand-binding domain (LBD) of the ecdysone receptor (EcR) of O. laevigatus was sequenced, and a homology protein model was constructed that confirmed a cavity structure with 12 α-helices, harbouring the natural insect moulting hormone 20-hydroxyecdysone. However, docking studies showed that a steric clash occurred for the DAH-based insecticides owing to a restricted extent of the ligand-binding cavity of the EcR of O. laevigatus.
  
  
  CONCLUSIONS
  The insect toxicity assays demonstrated that MACs are selective for O. laevigatus. The modelling/docking experiments are indications that these pesticides do not bind with the LBD-EcR of O. laevigatus and support the supposition that they show no biological effects in the predatory bug. These data help in explaining the compatible use of MACs together with predatory bugs in IPM programmes.
authors: Unidad de Protección de Cultivos, Escuela Técnica Superior de Ingenieros Agrónomos, Universidad Politécnica de Madrid, Madrid, Spain.
authors: Fermín
authors: F
authors: Amor
authors: Olivier
authors: O
authors: Christiaens
authors: Paloma
authors: P
authors: Bengochea
authors: Pilar
authors: P
authors: Medina
authors: Pierre
authors: P
authors: Rougé
authors: Elisa
authors: E
authors: Viñuela
authors: Guy
authors: G
authors: Smagghe
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D061046:Biological Control Agents; D020062:Heteroptera / Q000187:drug effects*; D006834:Hydrazines / Q000633:toxicity*; D019476:Insect Proteins / Q000737:chemistry; D007306:Insecticides / Q000633:toxicity*; D007605:Juvenile Hormones / Q000633:toxicity*; D008956:Models, Chemical; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010572:Pest Control, Biological; D010802:Phylogeny; D011987:Receptors, Steroid / Q000737:chemistry; D016415:Sequence Alignment; D013045:Species Specificity; D018675:Toxicity Tests
chemical_list: D061046:Biological Control Agents; D006834:Hydrazines; D019476:Insect Proteins; D007306:Insecticides; D007605:Juvenile Hormones; D011987:Receptors, Steroid; C055469:ecdysone receptor; C056565:1,2-dibenzoyl-tert-butylhydrazine; C406712:methoxyfenozide; C082026:tebufenozide