ANOVAs for the proportion of winged aphids.

Proportions were arcsine square-root transformed prior to analyses. The first analysis (a) was done without covariables, the second analysis (b) with biomass and nitrogen concentration of aphid host plants as covariables. “Plant species richness” and “Legume presence” were tested against “Plotcode”, all other terms against “Residuals”. Directions of significant effects of the covariables are indicated by arrows. P-values<0.05 are printed in bold. % SS = percent sum of squares explained.