Water vapour conductance of eggs during incubation
The water vapour conductance of whole eggs was significantly different to that calculated from allometric equations using the egg’s mass (df=19, T=3.86, p=0.001) (Figure 7A).
We compared the water vapour conductance calculated in this study for whole incubated eggs with that reported in the literature (Table 7). Calder (1978a) used infertile eggs and the methodology employed by Rahn et al., (1974). Sylin-Roberts (1983) devised a method for calculating the pore number and pore area and calculated the water vapour conductance of the whole egg from three eggshell fragments. Both these studies were done on Apteryx australis eggs and eggshells, but at this time, Apteryx australis included A. mantelli ,A. rowi , and A. australis .
We plotted the resulting water vapour conductance alongside the data published by Ar et al.,1974, where they demonstrated how the water vapour conductance is proportional to the 0.78 power of the eggs mass (Figure 8). Here we show how the water vapour conductance of Brown Kiwi fits perfectly with what is observed for other species.