Abstract: In order to understand the abundance and dynamics of thrips population in uncultivated vegetation, we investigated the species and number of thrips in several kinds of flowers from middle April to middle November at Maojiabu in West Lake landscaped area and analyzed the dynamics of Frankliniella intonsa, F. occidentalis,Thrips hawaiiensis and T. flavus from the flowers of Hypericum chinese, F. intonsa, F. occidentalis, Microcephalothrips sp of Erigeron annuus, F. intonsa, F. occidentalis and T. hawaiiensis of Alternanthera philoxeroides, and F. intonsa, T. hawaiiensis, T. flavus and Scirtothrips dorsalis of Canna indica. Six genus and sixteen species of thrips were observed in all sampled flowers, and the predominant species were F. intonsa, T. hawaiiensis and T. flavus. The predominant species on H. chinese was F. intonsa, and F. occidentalis, T. hawaiiensis and T. flavus occurred occasionally. T. hawaiiensis was the predominant species on E. annuus, the population reached peak in July, the late flower time. F. intonsa and F. occidentalis were the main species on A. philoxeroides at the time of early June and July. There were three peaks on the number of T. hawaiiensis and T. flavus on whole C. indica flower period, which was earlymiddle July, middlelate September and earlymiddle November. Meanwhile, the population was high and it reached the highest value of 101.60±13.89 per flower. The population of F. intonsa was much higher, which reached 12.60±4.35 per flower in the peak. In conclusion, F. intonsa have wide range of suitable plants, H. chinese, A. philoxeroides and C. indica except E. annuus were the suitable plants in this investigation, which could be the source of thrips. The suitable plant of T. hawaiiensis and T. flavus was C. indica, the suitable plant of F. occidentalis was A. philoxeroides and the suitable plant of Microcephalothrips sp was E. annuus in this investigation．

Key words: thrips, species, population dynamics, vegetation