Abstract:Recent reports suggested that when certain contaminants may present in aquatic ecosystem at levels, it would disruptendocrine functions of a variety of aquatic invertebrates. For this hypothesis, we sought to determine whether the estrogeniccompound Fenvalerate and androgenic compound TBTC can individually inhibit the development and reproductive output of thefreshwater rotifer Brachionus calyciflorus. The present study focused on the life history characteristics of B. calyciflorus undereffects of different concentrations of Fenvalerate and TBTC. The result showed that Fenvalerate and TBTC had significant effectson the durations of different development stages of B. calyciflorus and the characterristics of its population growth. Treatmentwith Fenvalerate at the concentrations of 200 and 1000μg/L significantly lengthened the duration of reproductive period.However, the duration of pre-reproductive, post-reproductive periods and the lifespan were shortened. In treatment with 1 and5μg/L TBTC, the number of eggs and population growth rate were also increased compared to the control, however, thepre-productive period was significantly lengthened, and the reproductive, post-reproductive periods and the lifespan weresignificantly shortened compared to the control. The total number of eggs and population growth rate were both decreasedsignificantly when the rotifer was exposed to 0.001 and 1-5μg/L of the above contaminants, and the number of eggs wascurve-related with the concentrations of Fenvalerate and TBTC (Fenvalerate: Y=-0.6745X2+6.6884X+5.855(R2=0.7027); TBTC:Y=0.2054X2-2.3178X+16.666(R2=0.6535)). Consequently, Fenvalerate and TBTC showed differently effects on the durations ofdifferent development stages of B. calyciflorus and the characterristics of its population growth.