Statistical analysis
Data for the grazing and developmental experiments were analyzed using a one-way ANOVA (α = 0.05). Bartlett’s test for equal variances was first run to test the assumption of equal variances. An arcsine transformation was necessary prior to analyses because data for the developmental portion of the experiments were represented as percentages. If the ANOVA indicated a significant effect of diet, Tukey’s one-way multiple comparisons was then used to analyze differences between individual treatments within a given experiment. The error rate for Tukey’s comparison was set at 0.05. Electivity indices were compared using the Wilcoxon signed-rank test (Sokal and Rohlf, 1981).