In Petri dishes, Coptotermes formosanus workers (100 or less) were placed with 0, 5, 10, or 20% soldiers. The juvenile hormone titers of these workers were monitored every two weeks for 8 weeks. Termites from two colonies were tested, each with 2 replicates for each sample date. Any changes in caste proportions were also noted at each sample date. On the first sample date, no pre-soldiers were observed and the JH levels in workers were similar among treatments with different soldier proportions. Over the next 3 sample dates, not surprisingly, pre-soldier formation increased in treatments with lower initial soldier proportion. Concurrently, the JH levels in workers were lower in treatments with high soldier proportions. This lower level of JH in workers with higher soldier proportion provides evidence that soldiers regulate JH level in workers.