title: Variability in development of the striped rice borer, Chilo suppressalis (Lepidoptera: Pyralidae), due to instar number and last instar duration.
abstract: The striped stem borer, Chilo suppressalis (Walker), is an important insect pest of rice which shows substantial variation in developmental duration among individuals. This variation is currently poorly characterized but it is important from a control perspective because pesticides can only target early sensitive instars. It is unclear whether there are key stages that determine the length of developmental duration of individuals and/or whether variation in instar number contributes to this variation. In this study, a laboratory population and a population recently established from the field were used to test variation in development time across instar stages. The duration of developmental time of C. suppressalis started to diverge from the 5thinstar onward. Individuals pupated at the 5th, 6th, 7thor even 8thinstar stage. In both populations, both the instar at which the larva pupated and the duration of the last larval instar stage determined total developmental time of an individual. There was little impact of the developmental time of early instars on total developmental duration or on instar number prior to pupation. Sex influenced the number of instars but not development time within this number. The biological and applied significance of uneven development in C. suppressalis are discussed.
authors.affiliation: Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China.
authors.forename: Guang-Hua
authors.initials: GH
authors.lastname: Luo
authors.affiliation: Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Yao
authors.affiliation: Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China.
authors.forename: Qiong
authors.initials: Q
authors.lastname: Yang
authors.affiliation: Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China.
authors.forename: Zhi-Chun
authors.initials: ZC
authors.lastname: Zhang
authors.affiliation: School of BioSciences, Bio 21 Institute, University of Melbourne, Parkville, Vic 3010, Australia.
authors.forename: Ary A
authors.initials: AA
authors.lastname: Hoffmann
authors.affiliation: Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China.
authors.forename: Ji-Chao
authors.initials: JC
authors.lastname: Fang
mesh_terms: D000818:Animals; D007814:Larva / Q000254:growth & development*; D007915:Lepidoptera / Q000254:growth & development / Q000472:pathogenicity* / Q000502:physiology; D012275:Oryza / Q000382:microbiology*