title: Diapause induction and termination in the small brown planthopper, Laodelphax striatellus (Hemiptera: Delphacidae).
abstract: The small brown planthopper, Laodelphax striatellus (Fallén) enters the photoperiodic induction of diapause as 3rd or 4th instar nymphs. The photoperiodic response curves in this planthopper showed a typical long-day response type with a critical daylength of approximately 11 h at 25 °C, 12 h at 22 and 20 °C and 12.5 h at 18 °C, and diapause induction was almost abrogated at 28 °C. The third stage was the most sensitive stage to photoperiod. The photoperiodic response curve at 20 °C showed a gradual decline in diapause incidence in ultra-long nights, and continuous darkness resulted in 100% development. The required number of days for a 50% response was distinctly different between the short- and long-night cycles, showing that the effect of one short night was equivalent to the effect of three long nights at 18 °C. The rearing day length of 12 h evoked a weaker intensity of diapause than did 10 and 11 h. The duration of diapause was significantly longer under the short daylength of 11 h than it was under the long daylength of 15 h. The optimal temperature for diapause termination was 26 and 28 °C. Chilling at 5 °C for different times did not shorten the duration of diapause but significantly lengthened it when chilling period was included. In autumn, 50% of the nymphs that hatched from late September to mid-October entered diapause in response to temperatures below 20 °C. The critical daylength in the field was between 12 h 10 min and 12 h 32 min (including twilight), which was nearly identical to the critical daylength of 12.5 h at 18 °C. In spring, overwintering nymphs began to emerge in early March-late March when the mean daily temperature rose to 10 °C or higher.
authors.affiliation: Institute of Entomology, Jiangxi Agricultural University, Nanchang, Jiangxi Province, China.
authors.forename: LiuFeng
authors.initials: L
authors.lastname: Wang
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: KeJian
authors.initials: K
authors.lastname: Lin
authors.affiliation: Institute of Entomology, Jiangxi Agricultural University, Nanchang, Jiangxi Province, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Chen
authors.affiliation: Institute of Entomology, Jiangxi Agricultural University, Nanchang, Jiangxi Province, China.
authors.forename: Shu
authors.initials: S
authors.lastname: Fu
authors.affiliation: Institute of Entomology, Jiangxi Agricultural University, Nanchang, Jiangxi Province, China.
authors.forename: FangSen
authors.initials: F
authors.lastname: Xue
mesh_terms: D000818:Animals; D006430:Hemiptera / Q000254:growth & development / Q000528:radiation effects*; D007814:Larva / Q000254:growth & development / Q000528:radiation effects; D008027:Light; D008675:Metamorphosis, Biological / Q000502:physiology / Q000528:radiation effects*; D009758:Nymph / Q000254:growth & development / Q000528:radiation effects; D017440:Photoperiod; D012621:Seasons; D013696:Temperature; D013997:Time Factors