All statistical analyses were perfo

All statistical analyses were performed with Statistica 6.0 for PC (StatSoft Inc., USA). Prior to parametric analyses, data were tested for normality using the Kolmogorov–Smirnov test, and for homogeneity of variances using the Bartlett's test. Data were loge transformed when necessary to meet the assumptions for parametric tests. We used two- way ANOVA (for tadpole mass at hatching, metamorphosis rate, metamorphosis time and variance of metamorphosis time) and MANOVA (for body size and mass at metamorphosis) with food supply and larval density as the factors to analyze data. Tukey's test was done on the variables that differed between the three density treatments. Throughout this paper, values were presented as mean ± 1 standard error (SE), and results were considered statistically significant at P b 0.05.