Effects of cumulative parthenogenetic generation and age of amictic female on the reproduction of rotifer Bra-chionus calyciflorus Effects of food concentration on the duration of reproductive period and the formation of mictic female in different strains of freshwater rotifer Brachionus calyciflorus The effect of vitamin E on reproduction of Brachionus calyciflorus (rotifer: monogononta) Effect of endocrine disruptors fenvalerate and TBTC on reproduction of rotifer Brachionus calyciflorus