Comparative anatomy of a mushroom body serotonergic neuron in the subcastes of the ant Pheidole dentata: Is there a relationship to division of labor?

The ant Pheidole dentata has been a model of caste evolution and polyethism. Minors expand their task performance and show age-related increases in brain serotonin and the number of serotonergic neurons in the optic lobe. Synaptic pruning also correlates with increases in task repertoire. To further investigate the relationship between subcaste, age and neural organization, we examined a single, highly conserved serotonergic neuron that innervates the mushroom bodies. We compared patterns of innervation between young and old majors and minors to understand the potential role of this neuron to division of labor.