Abstract: This paper examined the acute toxicities of glyphosate and paraquat to Moina macrocopa, and studied the effects of the sub-lethal concentrations of paraquat (0, 0.01, and 0.04 mg·L^-1) and glyphosate (0, 0.4, and 1.6 mg·L^-1) on the lifetable demography of this cladoceran. The 48 h LC₅₀ values of glyphosate and paraquat to M. macrocopa were 0.626 mg·L^-1 and 26.287 mg·L^-1, respectively. Paraquat concentration had significant effects on the life expectancy at birth, generation time, net reproductive rate, and intrinsic rate of population increase (P<0.01), and glyphosate concentration affected the life expectancy at birth, generation time, and intrinsic rate of population increase significantly (P<0.01). The interaction between the two herbicides had significant effects on the generation time and intrinsic rate of population increase of M. macrocopa (P<0.01). Multiple comparisons indicated that regardless of the effect of glyphosate, the paraquat at 0.01 mg·L^-1 had significant effect on the increase of the life expectancy at birth, but the reverse was also true for the paraquat at 0.04 mg·L^-1. The paraquat at 0.04 mg·L^-1 decreased the net reproductive rate of M. macrocopa significantly. Regardless of the effect of paraquat,
 the glyphosate at 0.4 and 1.6 mg·L^-1 decreased the life expectancy at birth significantly. Compared with the blank control, the mixture of paraquat at 0.01 mg·L^-1 and glyphosate at 1.6 mg·L^-1 increased the generation time significantly, but the mixture of paraquat at 0.04 mg·L^-1 and glyphosate at 0, 0.4, and 1.6 mg·L^-1 decreased the generation time and the intrinsic rate of population increase. With the increase of glyphosate concentration, the toxicity of paraquat at 0.04 mg·L^-1 to M. macrocopa decreased significantly, suggesting a significant antagonism existed between paraquat and glyphosate.

Key words: subtropical zone, evergreen broadleaved forest, biomass estimation, biomass allometric equation.