Effect of sex and size on copper susceptibility of the common guppy, Lebistes reticulatus (Peter)

Multiple regression analyses were conducted to relate rate of toxic action, body weight and concentration for fry, male and female populations of Lebistes reticulatus exposed to copper solutions. For each of these three populations, copper susceptibility decreased as body weight increased. On the basis of the rate of toxic action adjusted with the size factor, the copper susceptibility differed significantly among the fry, male and female populations at the ratios of 2.20:1.55:1.00. When the size factor was not included in calculation, the rate of toxic action or median survival time did not show such a difference between the males and females.