摘要:We collected the three dominant cladoceran species from Valle de Bravo, a 1, 730 ha drinking water reservoir in tropical Mexico and found a direct positive relation between carapace length (Y in μm) and the dry weight (X in pg) for all the three species. For Daphnia laevis, the relationship was In Y = −2.51 0.86 In X; for Chydorus sphaericus, In Y = −21.00 4.16 In X; and for Bosmina longirostris, In Y = −8.16 1.85 In X.