Pore radii
The average pore radius was measured using SEM images of the external layer. Only images that showed opened pores in which the diameter could be measured were used (N=87), these images belonged to 28 individual eggs, and we used ImageJ to take three measurements of diameter per pore. These measurements were subsequently divided by two to estimate the radius and the radii were averaged per individual pore. A species average was used for further calculations and individual averages were used to compare with microCT radius measurements. However, no statistical model was used due to the small sample size per species used in the microCT.