High performance liquid chromatography studies on the polysaccharides in the walls of the mounds of two species of termite in Senegal, Cubitermes oculatus and Macrotermes subhyalinus: their origin and contribution to structural stability

The origin, nature and quantity of polysaccharides in the walls of the epig eal mounds of a species of soil-feeding termite, Cubitermes oculatus, and a fungus-growing termite, Macrotermes subhyalinus, found in Senegal, and of soil not considered to be under the influence of termites, were studied to obtain a clearer picture of the structural stability of these materials. Th e compounds were extracted and analysed by high performance liquid chromato graphy. We found that the walls of mounds made by soil-feeding species were very rich in sugars soluble in aqueous acid or hot water. Most of the suga rs originated from cellulose and hemicellulose, and only a small proportion from microorganisms. There were also significant amounts of stachyose in t he mound walls and in the reference soil. This sugar was probably formed by the surrounding vegetation, which was mainly leguminous crops. Comparison of the mineral and organic-mineral particle sizes of samples confirmed that the walls of soil-feeding termite mounds where there is the greatest redis tribution of clay have the best aggregating capacity. The results therefore show that the polysaccharides in mound walls of soil-feeding termites are mostly of plant origin. Their influence on the stability of these structure is discussed. The walls of fungus-growing termite mounds contain little or ganic matter and hence low levels of polysaccharides, which are mainly of p lant origin.