AbstractThe aim of this study was to determine thrips abundance, species composition, sex ratio and seasonal dynamics of these insects on two morphological forms of Andean lupin (epigonal and semiepigonal). Thrips were studied in the lupine plants sown at two dates at the Experimental Research Station at Pawłowice, near Wrocław, Lower Silesia, Poland, during two growing seasons (2011-2012). The experiment was designed as a split-plot with four replicates for each morphological form and time of sowing. For the determination of thrips species’ composition, plants were collected from the central part of each plot when lupin was at the full blooming stage. In the laboratory, plants were shaken over a sheet of white paper. Once in each season thrips were also collected with a sweep net. In the laboratory larvae and adults were identified to species level and separated into males and females. During the whole lupin growing season, insects were also counted weekly on 10 consecutive plants in the middle row of each plot. Frankliniella intonsa, Thrips major and Aeolothrips intermedius were the dominant species in the full blooming stage of both semiepigonal and epigonal forms of Andean lupin. Thrips tabaci also occurred in greater numbers. There were no significant differences between numbers of thrips and number of species occurring on semiepigonal and epigonal plants sown at the same time. In the most numerous species, like F. intonsa and T. major, mainly females occurred in their population. In the population of A. intermedius males were abundant. Thrips occurring in Lupinus mutabilis, irrespective of the used form of lupin or sowing time, had one peak of abundance, i.e., the last ten days of June and the first ten days of July, when plants were at the blooming stage.