Ref ID : 779
T. Ramakrishna Rao and S.S.S. Sarma; Demographic parameters of Brachionus patulus Muller (Rotifera) exposed to sublethal DDT concentrations at low and high food levels. Hydrobiologia 139:193-200, 1986
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The combined effects of sublethal levels of DDT (0, 15, 30, 45, and 60 ug/L) and food (Chlorella at 1 and 3x10E6 cells/ml) on the demography of the rotifer Brachionus patulus were studied. The average lifespan, life expectancy, net reproduction rate (Ro) and intrinsic rate of increase (r) were significantly greater at the higher food level, but declined with increasing DDT concentration. A significant DDT-food interaction was manifested in the toxicity-mitigating action of the higher food density at higher DDT levels. The (r) values were negative at DDT levels 30 ug/L and above, only when food density was low. The effective DDT concentration at which a given parameter value was reduced to 50% of that in the controls (EC50) was lower at lower food levels for both survivorship and reproduction, and lower for reproduction than for survivorship at either food level.