Fig. 1.

Alpha diversity of eggshells of wild woodlarks and skylarks. Phylotype richness a and Shannon diversity b of eggshell bacterial communities, stratified by lark species and laying sequence. Alpha diversity metrics are compared to data from maternal and environmental communities (faded boxes) [25]. Significance of comparisons among first and second eggs, and between eggshells and other communities are shown (**P < 0.01, ***P < 0.001, ns not significant, other non-significant pairwise differences are not highlighted)