Fig. 3. Tyramine ß-hydroxylase (T ßh) activity in honey bee brains. T ßh activity from bees from single-cohort colonies (SCC, normal-aged nurses and precocious foragers) and typical colonies (TC, typical foragers and typical nurses) are shown. Values are mean ± s.e.m.; sample size is indicated in each bar. ^*Significant differences between nurses and foragers (ANOVA and Fisher PLSD post-hoc tests). The results of two-way ANOVAs for T ßh activity as a function of behavior and colony type are also shown. Seven trials were performed; see Fig. 1 legend.