In Australia, laboratory bioassays with subterranean termites typically contain groups of workers and soldiers in a substrate of mound material, and/or vermiculite and sawdust. However, the termite substrate used may affect termite consumption. This hypothesis was tested using five different colonies of Coptotermes acinaciformis (Froggatt). Blocks of Pinus radiata (D. Don) 20 × 20 × 5 mm were exposed in two different substrates to one gram of termites from five colonies for 56 days, and the wood consumption rate was calculated. Termites did not always behave similarly on the different substrates. The amount of wood consumed in the sand/mound material substrate was significantly higher than in mound material alone. The use of termite mound material as a major substrate did not encourage maximum termite feeding of the wood blocks.