title: Use of a pollen-based diet to expose the ladybird beetle Propylea japonica to insecticidal proteins.
abstract: A rape seed pollen-based diet was developed and found to be suitable for use in a dietary exposure assay for Propylea japonica. Using the diet, we established and validated a dietary exposure assay by using the protease inhibitor E-64 as positive control. Dose-dependent responses were documented for all observed life-table parameters of P. japonica including survival, pupation and eclosion rates, development time and adult weight. Results suggested that the dietary assay can detect the effects of insecticidal compounds on the survival and development of P. japonica. Using the established dietary assay, we subsequently tested the toxicity of Cry1Ab, Cry1Ac and Cry1F proteins that are expressed by transgenic maize, cotton or rice plants to P. japonica larvae. The diet containing E-64 was included as a positive control. Survival and development of P. japonica larvae were not adversely affected when the diet contained purified Cry1Ab, Cry1Ac, or Cry1F at 500 µg/g diet representing a worst-case exposure scenario. In contrast, P. japonica larvae were adversely affected when the diet contained E-64. The bioactivity and stability of the Cry proteins in the diet and Cry protein uptake by the ladybird larvae were confirmed by bioassay with a Cry-sensitive insect species and by ELISA. The current study describes a suitable experimental system for assessing the potential effects of gut-active insecticidal compounds on ladybird beetle larvae. The experiments with the Cry proteins demonstrate that P. japonica larvae are not sensitive to Cry1Ab, Cry1Ac and Cry1F.
authors.affiliation: College of Life Science, Henan Agricultural University, Zhengzhou, China ; State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China.
authors.forename: Xiaojie
authors.initials: X
authors.lastname: Zhang
authors.affiliation: State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China.
authors.forename: Yunhe
authors.initials: Y
authors.lastname: Li
authors.affiliation: State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China ; Agroscope, Institute for Sustainability Sciences ISS, Zurich, Switzerland.
authors.forename: Jörg
authors.initials: J
authors.lastname: Romeis
authors.affiliation: College of Life Science, Henan Agricultural University, Zhengzhou, China.
authors.forename: Xinming
authors.initials: X
authors.lastname: Yin
authors.affiliation: State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China.
authors.forename: Kongming
authors.initials: K
authors.lastname: Wu
authors.affiliation: State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China.
authors.forename: Yufa
authors.initials: Y
authors.lastname: Peng
mesh_terms: D000821:Animal Feed; D000818:Animals; D001517:Coleoptera / Q000187:drug effects* / Q000502:physiology*; D004032:Diet; D005260:Female; D007306:Insecticides / Q000008:administration & dosage*; D007814:Larva; D008297:Male; D011058:Pollen; D012639:Seeds
chemical_list: D007306:Insecticides