Fig. 5. Tßh gene expression in honey bee brains. Cycle threshold (Ct) was determined using second derivative analysis and the difference in Ct between AmTßh and a control gene was used to determine relative expression levels. aTßh mRNA levels from single bees collected from single-cohort colonies (normal-aged nurses and precocious foragers) and typical colonies (typical foragers and typical nurses) are shown. Values are means ± s.e.m.; sample size is indicated in each bar. ^*Significant differences between nurses and foragers (ANOVA and Fisher PLSD post-hoc tests). Results of two-way ANOVA for T ßh expression as a function of behavior and colony type are also shown. Three trials were conducted (the same trials as in Fig. 1, and corresponding to Trials 1, 2 and 3 of Fig. 3).