Brain subregions scale differently with brain size across Pheidole worker groups.

We tested whether worker groups shared common scaling slopes, whether there were deviations from isometric scaling (β = 1), and whether there were significant shifts among worker groups in scaling elevation (grade shifts) or position along the x-axis (Figure 4, [51]). Values in parentheses indicate 95% confidence intervals of slopes (column 3) or statistical details (χ2-tests, column 4; Wald tests, columns 5 and 6). All variables ln-transformed before analysis. CBV, central brain volume; ROCBV, remainder-of-central-brain volume.