We used antimicrobial compounds as a subtractive tool to test the hypothesis that, in addition to endogenous termite and protistcontributed enzymes, prokaryotic symbionts play a role in the lignocellulase potential of the R. flavipes hindgut. Four commercially available antimicrobials were used: 1) ampicillin, a cell wall synthesis inhibitor of gram-positive bacteria; 2) kanamycin, a broad-spectrum antibiotic causing misreading of mRNAs during translation; 3) metronidazole, an anti-protozoal/anti-anaerobe which binds DNA preventing nucleic acid synthesis/replication; and 4) tetracycline, a broad-spectrum antibiotic which interferes with translation by preventing tRNA binding at the ribosome (Walker, 1996).