Abstract: To investigate the effects of elevated atmospheric CO₂ concentration on population dynamics of the western flower thrips (Frankliniella occidentalis) and their host plant, kidney bean (Phaseolus vulgaris), this paper measured the growth, development duration and reproduction of the thrips and the leaf nutrients of their host plant in two different CO₂ concentration chambers (800 vs. 400 μL·L^-1). The results indicated that the elevated CO₂ concentration changed the nutritional ingredients of kidney bean leaves, which affected the growth, development, reproduction of F. occidentalis. High CO₂ concentration significantly reduced the leaf gross crude protein contents (GP) of kidney bean; however, the contents of total saccharides (TSCs), starch, and soluble protein and free amino acids of leaves were significantly enhanced. Compared with the control (400 μL·L^-1 CO₂), the egg stage, 1st instar larva stage, 2nd instar larva stage of F. occidentalis were significantly decreased in the doubled CO₂ concentration treatment (800 μL·L^-1 CO₂), yet the oviposition rate of individual female increased by 9.74% (P<0.05). Under the higher CO₂ concentration, the net reproductive rate (R₀), intrinsic increase rate (r_m), increase rate per unit (λ) of F. occidentalis were increased by 7.40%, 8.86% and 1.32%, respectively (P<0.05). Compared with the thrips in 400 μL·L^-1 CO₂ concentration chambers, the generation time (T) and the time of doubling population size (DT) of those in 800 μL·L^-1 CO₂ concentration decreased by 1.42 and 0.38 d, respectively (P<0.05). R₀, r_m and λ of F. occidentalis were proved to have negative correlation with the content of gross crude protein and positive correlation with TSCs/GP and starch of kidney bean leaf. In contrast, T, DT of F. occidentalis had significant positive correlation with the content of gross crude protein of P. vulgaris, and negative correlations were observed among T, DT of F. occidentalis and TSCs/GP, starch, free amino acids in leaf of P. vulgaris.

Key words: distribution, tree species, association between families., composition, forest