Geographical variations in life histories of Plutella xylostella in China

The diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), is one of the most important pests of crucifers worldwide. Susceptibility to insecticides and host plants of P. xylostella vary geographically. To investigate local adaptation, we measured the variation of the biology, life-histories and life-table parameters of P. xylostella populations from five widely ranging geographical regions in China, Beijing (BJ), Shandong (SD), Shaanxi (SX), Yunnan (YN), and Guangdong (GD), using the same variety of cabbage (Brassicae oleracea L. var. capitata; var. "Qingan 80'') as the food plant at the same temperature in the laboratory. Principal components analysis showed the life-history and life-table parameters of P. xylostella differed among the five geographical populations. The first component, including female fecundity and adult longevity and male adult longevity, accounted for the most variation among the five geographical regions, which can be classified into three groups: BJ-SX, YN-GD, and SD. The intrinsic rate of increase (r(m)) was greatest in BJ and SX, intermediate for GD and YN, and the lowest for SD, whereas mean generation time (T) was greatest in SD, intermediate for YN and GD, and the lowest for BJ and SX. These variations reflect the importance of local genetic adaptation and should be considered when planning management of P. xylostella in China.