Fig. 4. (A) Mass of dry yolk solids consumed (predicted initial egg yolk solids – measured residual yolk solids) by embryos during development increases with yolk-free hatchling mass (M_yc=0.29M_yfh–3.94; r²=0.52). (B) Mass of residual yolk solids rM decreased as mass of yolk-free hatchling increased irrespective of initial egg mass (rM_ryd=–1.03rM_yfhd+0.41; r²=0.58). Statistical residuals from the regression of the mass of residual yolk solids and the mass of yolk-free hatchling on initial egg mass were obtained from regression equations in Figs 1 and 3 and plotted against each other, revealing a trade-off between retaining residual yolk and producing a hatchling.