Age distribution in colonies 1–17. (Worker age was determined from adult emergence to colony freezing. Colony name reflects its social structure: PCP, pre-competition phase; CP, competition phase; QL, queenless colonies. All colonies except 7CP were normally distributed. There were no significant differences in age distributions between the 17 colonies, either considering the means (Kruskal–Wallis ANOVA test: H (16, n=783)=17.48, p=0.35) or the medians of the 17 colonies (Χ162=10.11027, p=0.86).)