title: Imidazole derivative KK-42 boosts pupal diapause incidence and delays diapause termination in several insect species.
abstract: The imidazole derivative KK-42 is a synthetic insect growth regulator known previously to be capable of averting embryonic diapause in several Lepidoptera, but whether it also affects diapauses occurring in other developmental stages remains unknown. In the present study, we examined the effect of KK-42 on pupal diapause in two species of Lepidoptera, the Chinese oak silkworm Antheraea pernyi and the corn earworm Helicoverpa zea, and in one species of Diptera, the flesh fly Sarcophaga crassipalpis. In A. pernyi, KK-42 delayed pupal diapause termination under the long day conditions that normally break diapause in this species. Likewise, in H. zea, KK-42 delayed termination of pupal diapause, a diapause that, in this species, is normally broken by high temperature. KK-42-treated pupae of these two species eventually terminated diapause and successfully emerged as adults, but the timing of diapause termination was significantly delayed. KK-42 also significantly increased the incidence of pupal diapause in H. zea and S. crassipalpis when administered to larvae that were environmentally programmed for diapause, but it was not capable of inducing pupal diapause in H. zea if larvae were reared under environmental conditions that do not normally evoke the diapause response. Experiments with H. zea showed that the effect of KK-42 on pupal diapause was dose- and stage-dependent, but not temperature-dependent. Results presented here are consistent with a link between KK-42 and the ecdysteroid signaling pathway that regulates pupal diapause.
authors: Department of Sericulture, College of Bioscience and Biotechnology, Shenyang Agricultural University, Shenyang 110866, China; Departments of Entomology and Evolution, Ecology, and Organismal Biology, The Ohio State University, Columbus, OH 43210, USA. Electronic address: liuyanqun@syau.edu.cn.
authors: Yanqun
authors: Y
authors: Liu
authors: Departments of Entomology and Evolution, Ecology, and Organismal Biology, The Ohio State University, Columbus, OH 43210, USA.
authors: Qirui
authors: Q
authors: Zhang
authors: Departments of Entomology and Evolution, Ecology, and Organismal Biology, The Ohio State University, Columbus, OH 43210, USA. Electronic address: denlinger.1@osu.edu.
authors: David L
authors: DL
authors: Denlinger
mesh_terms: D000818:Animals; D064666:Diapause, Insect / Q000187:drug effects*; D007093:Imidazoles / Q000494:pharmacology*; D007605:Juvenile Hormones / Q000494:pharmacology*; D007814:Larva / Q000187:drug effects / Q000254:growth & development; D009036:Moths / Q000187:drug effects / Q000254:growth & development*; D017440:Photoperiod; D011679:Pupa / Q000187:drug effects / Q000254:growth & development; D058493:Sarcophagidae / Q000187:drug effects* / Q000254:growth & development*; D013045:Species Specificity; D013696:Temperature
chemical_list: D007093:Imidazoles; D007605:Juvenile Hormones; C063652:1-benzyl-5-(2,6-dimethyl-1,5-heptadienyl)imidazole
keywords: Antheraea pernyi; Helicoverpa zea; KK-42; Pupal diapause; Sarcophaga crassipalpis