MICROBIAL ACTIVITY IN THE MOUNDS OF SOME AUSTRALIAN TERMITES

In this study I have measured the microbial biomass of soil and stored food material in the mounds of six northeastern Australian termite sp ecies using a combination of substrate-induced respiration (SIR) and f umigation extraction techniques. In all but one case mound soil was si gnificantly higher in microbial biomass than nearby surface soils. The microbial biomass of Coptotermes acinaciformis mound material was app roximately six times that of the surface soil. The mean microbial biom ass content of grass stored in chambers of Nasutitermes magnus, Tumuli termes pastinator and Drepanotermes rubriceps mounds was also very hig h, up to 2830 mu g C g grass(-1), which was approximately 20 times gre ater than the mound soil microbial biomass. It is suggested that micro bial decomposition of this food material prior to ingestion by the ter mites may provide the termite colony with a food source relatively enr iched in nitrogen. The microbial decomposition of food material stored in the outer chambers of the mound of an Australian termite has some analogy with the behaviour of the fungus cultivating Macrotermitinae o f the African and Asian regions. The association between mound-buildin g termites and microorganisms present in their mounds is discussed in relation to organic matter decomposition. (C) 1998 Elsevier Science B. V.