highly significantP < 0.0008
A pooled analysis of all data showed a highly significant effect of colony environment on aggression (analysis of z-scores: whole model: F 18,982 = 2.43, P < 0.0008, foster colony aggression level: F 1 = 17.3, P < 0.0001, worker genotype: F 17 = 1.6, P < 0.069; the interaction term was non-significant and so excluded).