Table 2.

The effects of egg-producer and father age on egg size

Egg trait	Covariate	Effect size (10‐3mm/day)	Standard errors	z-score	P
Length	Egg-producer age	0.781	0.515	1.515	0.130
	Father age	0.179	0.445	0.402	0.688
	Egg-producer age × father age	‐1.551	0.690	‐2.246	0.025
Width	Egg-producer age	‐0.053	0.446	‐0.118	0.906
	Father age	‐0.044	0.392	‐0.113	0.910
	Egg-producer age × father age	‐0.580	0.596	‐0.974	0.330

The units of egg length and width are in mm. Effects that were significant to a threshold of α = 0.05 are in boldface. Full model results are given in Supplementary Table S4.