Microbial activity in the mounds of some Australian termites

Abstract

In this study I have measured the microbial biomass of soil and stored food material in the mounds of six northeastern Australian termite species using a combination of substrate-induced respiration (SIR) and fumigation extraction techniques. In all but one case mound soil was significantly higher in microbial biomass than nearby surface soils. The microbial biomass of Coptotermes acinaciformis mound material was approximately six times that of the surface soil. The mean microbial biomass content of grass stored in chambers of Nasutitermes magnus, Tumulitermes pastinator and Drepanotermes rubriceps mounds was also very high, up to 2830 μg C g grass −1, which was approximately 20 times greater than the mound soil microbial biomass. It is suggested that microbial decomposition of this food material prior to ingestion by the termites may provide the termite colony with a food source relatively enriched 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 of the African and Asian regions. The association between mound-building termites and microorganisms present in their mounds is discussed in relation to organic matter decomposition.