Abstract:Propylaea japonica adults and newly-hatched larvae were collected from different planting areas, including monocultured transgenic Bacillus thuringiensis (Bt) cotton area over five years, transition area with Bt cotton intercropped with maize and other crops, and non-Bt area of monocultured orchard over 30 years. P.japonica larvae were fed with GK12-originated aphid, Bt cotton-originated aphid and non-Bt aphid alternatively, and non-Bt aphid, according to the sources of the larvae. Adult body size and body mass, larval development and fecundity of the second generation were compared. The results showed that body size of field collected P.japonica adults were ranked as Bt cotton areatransition area>non-Bt area. Body mass of newly emerged adults were ranked as Bt cotton areaP.japonica from different planting areas differed significantly. Compared with individuals from transition area and non-Bt area, P.japonica adults collected from Bt cotton area were smaller, larval development periods were longer, newly emerged adults were smaller, fewer females emerged, and females laid less eggs.