Figure 5.

(a) Size distribution of (i) female (n = 261, mean = 5.051, s.d. = 0.233) and (ii) male (n = 60, mean = 4.674, s.d. = 0.253) eggs produced by mated mothers. The statistical analysis was performed taking into account a random mother effect nested within egg sex. (b) Box plot for the size of female and male eggs produced by mated mothers. (c) Mixed logistic regression of individual egg sex on egg size, performed on eggs produced by mated females. Dark line, mean predicted value; individual symbols (♂ and ♀), best linear unbiased predictors (which depend on the random factor mother). Circles which take the values ‘0’ or ‘1’ indicate the observed data. Colours indicate the sex (blue, male; red, females).