Effects of FSH on population growth rate of females (ht) and males (mt) of the rotifer Brachionus calyciflorus. Population growth rate (r) is offspring per female per day, and that of males depends on the production of sex cycle of the female. Boxes indicate minimum and maximum values. Vertical lines on boxes indicate standard deviations. Asterisks (*) represent significant differences with respect to control (p > 0.05). N = 6.