Biological Variations Of Plutella Xylostella Populations From Five Different Geographic Origins

The diamondback moth, Plutella xylostella (L.)(Lepidoptera: Plutellidae), is one of themost important pests of crucifers worldwide. Susceptibility to insecticides or host plants of P.xylostella varied geographically. To investigate local adaptation, we measured the variation ofthe biology, life histories and life-table parameters of P. xylostella populations, it can confirmthe dynamic of different geographical P. xylostella populations, and provides the theoreticalbasis for prevention. The main results are as follows:1. In this study, we collected P. xylostella from five geographic regions in China,Beijing (BJ), Shandong (SD, Taian), Shaanxi (SX, Yangling), Yunnan (YN, Kunming), andGuangdong (GD, Guangzhou) using the same variety of cabbage (B. oleracea L. var. capitata;var.‘Qingan80’) as the food plant at the same temperature in the laboratory [25±1°C (day),22±1°C (night),65±5%RH and a photoperiod of14L:10D h]. The larval developmenttime in SX was shortest (6.83d), followed BJ (6.99d), the longest in SD (9.64d). Thefecundity of YN (385.41) and GD (411.47) are highest, there was no significant difference inBJ (344.76)、SX (337.18) and SD (342.74).2. Principal components analysis (PCA) showed that the life history and life tableparameters of P. xylostella differed among the five geographical populations. The firstcomponent, including female fecundity and adult longevity and male adult longevity,accounted for the most variation among the five geographic regions, which can be classedinto three groups: BJ-SX, YN-GD, and SD. The intrinsic rate of increase (rm) was greatest inBJ and SX, intermediate for GD and YN, and the lowest for SD, whereas mean generationtime (T) was greatest in SD, intermediate for YN and GD, and the lowest for BJ and SX.3. The results showed that there were significant differences in the five different P.xylostella populations in development time, adult longevity, fecundity and oviposition timeunder laboratory condition. This difference maybe also exist in field. These variations reflectthe importance of local genetic adaptation when planning management of P. xylostella inChina.