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.