Bar graphs of morphological and life-history trait means Daphnia populations in fishless and fish lakes. Fishless populations are shown in black and populations co-occuring with fish in white. A) body sizes; B) clutch sizes; C) offspring sizes; D) instar-specific ages. Bars represent the mean with error bars = 2SE. Significance levels for differences in trait means generated by a NANOVA (* = p < 0.05; ** = p,0.01; *** = p < 0.001). See text for further explanation of trait designations and analysis.