Social insects offer powerful models to investigate mechanisms of elaborate individual behaviors comprising a cooperative community. Workers of the leafcutter ant genus Atta are extreme examples of behavioral segregation among phenotypically distinct worker types. We utilize this worker system to test the molecular underpinnings of behavioral programming and the extent of plasticity to reprogramming. We identify specific neuropeptides mediating worker division of labor in A. cephalotes, finding two neuropeptides associated with characteristic behaviors of leaf cutting and of brood care. Genetic knockdown or injection of these neuropeptides led to a stark gain or loss of each behavior and to transcriptomic shifts toward gene pathways expressed in the natural castes. We also reveal global similarities between worker transcriptomes of the eusocial mammal, the naked mole-rat H. glaber, with orthologous A. cephalotes workers. This work underscores the essential function of neuropeptides in establishing complex social behavior and a remarkable plasticity among individual behavioral types.