Hatching success of queen- and worker-laid eggs at different levels of relative humidity. Thirty eggs were incubated per colony. Means ± standard deviations are given (n = 3 pairs of colonies). Effects of egg type (queen- or worker-laid), relative humidity and forceps transfer were all significant (ANOVA, P < 0.001 in all three cases). The interaction between egg type and relative humidity was also significant (P = 0.02), while other interactions were not (P > 0.07).